Okra or lady's finger, Abelmoschus esculentus L., locally known as bhendi, or dheros is a popular and most common vegetable crop in Bangladesh and in other tropical and sub- tropical parts of the world. It belongs to the family Malvaceae and originated in tropical Africa. Okra is an upright annual, herbaceous 3 to 6 feet tall plant with a hibiscus-like flower. It is a tropical direct sown vegetable with duration of 90-100 days. Though okra is produced mainly in the kharif season (Feb-July), it can be grown in year-round. It occupies an area of 3.70 lakh ha with an annual production of 36.57 lakh ton and average yield of 9.88 ton/ha during 2005-06. Okra is a popular nutritious fruit vegetable. It contains large amount of Vitamin A, B & C and also contains Ca++ & protein. Okra is cultivated mainly for its immature fruits, which are generally cooked as vegetable. Tender fruits have high mucilage content and are used in soups and gravies. The fruits also have some medicinal value. A mucilaginous preparation from the pod can be used for plasma replacement or blood volume expansion. Besides being a vegetable, it acts as clarifying agent in jaggery preparation. Fiber derived from the stem of okra plant is used for rope making. Okra is said to be very useful against genitourinary disorders, sperma-torrhoea and chronic dysentery (Sharif et al., 2019).

Okra production in Bangladesh is affected by many factors, among them insect pest attack is the major one. Since okra belongs to the family Malvaceae, nineteen insect pests and four mites have been reported on okra of which the sucking pest complex create havoc by causing both quantitative and qualitative loss to the crop. Leaves are mainly infested by sucking insect pests. There are four main sucking insect pests of okra in Bangladesh. Aphid, Myzus persicae, Sulzer; soft-bodied, pear-shaped insects with a pair of dark cornicles and a cauda protruding from the abdomen; yellow-green nymph, may be winged or wingless but later is most common. These are known to feed in colonies. Aphids can attain very high densities on young plant tissue, causing water stress, wilting, and reduced growth rate of the plant (Pawar et al. 2000). Jassid, Amrasca biguttula biguttula, Ishida ; the adults are wedge shaped (2 mm) pale green with a black spot on posterior half of each of the fore wings. The female inserts about 15 yellow eggs into leaf veins on the underside. Nymphs and adults suck sap usually from the under surface of the leaves and inject toxins causing curling of leaf edges and leaves turn red or brown called as ‘Hopper Burn' (Patel and Patel, 1996). The leaves dry up and shed. On transformations into winged adults, they feed constantly on the plant juice.

Whitefly, Bemisia tabaci, Gennadius; the insect breeds throughout the year and the female lays stalked yellow spindle shaped eggs singly on the lower surface of the leaf. Nymphs and adults suck the sap usually from the under surface of the leaves and excrete honeydew. Leaves appear sickly and get coated with sooty mold. The whitefly serves as the vector for the spread of yellow vein mosaic disease causing damage to okra crop. Mealybug, Pseudococcus hirsutus, Green; they have sucking mouthparts to extract large amount of sap from the host plant. These insects extract a large amount of sap in order to obtain enough proteins; the excess sap is excreted as honeydew. The excreted honeydew attracts ants and act as a medium for the growth of sooty mould which inhibits the plants ability to manufacture food. Ants in turn protect the mealybug for a continued supply of honeydew, which in turn can damage or kill plants. In Bangladesh okra sucking pests severely attack the leaves of okra and reduce the yield of okra. Farmers always desire quick curative action for controlling pests. Since no other control measure against okra sucking pests is available, chemical insecticides have remained as the most powerful tools for controlling this pest. Insecticides are highly effective, rapid in curative action, adaptable to most situations and relatively economical. Insecticides are the only tool for pest management which is reliable for emergency action when insect pest population approach or exceed the economic threshold level. But this is not environment friendly. This is also harmful for human consumption (Uddin et al., 2023).

The management of sucking pest of okra through various plant materials was limited throughout the world. Management practices of aphid on okra in Bangladesh and other countries are still limited to frequent spray of toxic chemical pesticides (Patel et al., 1996, Chitra et al., 1997, Rathod et al., 2002). Beside the chemical product; plant product also mixed with animal product to reduce the aphid (Ukey et al., 1999). Jassid population including adult and nymph may also be reduced through use of plant materials (Natarajan et al., 2000, Rosaiah, (2001a). Whitefly and mealybug population was also reduced through chemical insecticide as well as plant materials (Ahmad et al., 1995, Chandrashekharappa, 1995, Tatagar, 2002). The use of insecticide is a burning issue in respect of agro socio economic and environmental aspect. For that reason, we should use botanicals for effective management of insect pests. At present situation in Bangladesh, there is a great need of information about appropriate management of sucking insect pests of okra using botanicals.

Objectives

Considering the above situation the present study was, therefore, undertaken with the following objectives:

• To know the infestation status of sucking insect pests on okra.
• To evaluate the efficacy of some plant extracts against the sucking insect pests of okra
• To identify the effective plant extracts for the management of sucking insect pests of okra.

Location of the experimental plot

The experiment was conducted at the Farm of Sher-e-Bangla Agricultural University, Dhaka during the period from April to September 2011. The site is 23⁰ 46^' N and 90⁰24 ^' E Latitude and at Altitude of 9m from the sea level.

Characteristics of soil

The soil of the experimental site is a medium high land belonging to the Modhupur Tract under the Agro Ecological Zone (AEZ) 28. The soil texture was silty loam with a pH 6.7. Soil samples of the experimental plot was collected from a depth of 0 to 30 cm before conducting the experiment and analyzed in the Soil Resources Development Institute (SRDI), Farmgate, Dhaka. Details of the mechanical analysis of soil sample are shown in Appendix I. The experimental site was a medium high land. The morphological charac-ters of soil of the experimental plots as indicated.

Climate

The weather condition of the experimental site was under the sub-tropical monsoon climate, which is characterized by heavy rainfall during kharif season (April to September, 2011) and scantly in the Rabi season (October to March, 2011). There was no rain fall during the month of December, January and February. The average maximum temperature during the period of experiment was 35.10°C and the average minimum temperature was 30.40°C. Details of the meteorological data in respect of temperature, rainfall and relative humidity the period of the experiment were collected from Bangladesh Meteorological Department, Agargoan, Dhaka- 1207, Dhaka.

Planting materials used for experiment

The okra variety “BARI Dherosh-1''was used in this study which was resistant to yellow vein mosaic virus, a severe disease of okra. It was an open pollinated high yielding variety developed by the Vegetable Division of Horticulture Research Center, Bangladesh Agri-cultural Research Institute (BARI), Gazipur. The variety was released for commercial cultivation in 1996.

Treatments of the Experiment

Nine treatments were considered in this experiment. These are as follows:

T₁ = Ripcord 10EC @ 1ml/L of water at 7 days inter-val.

T₂ = Tamarind (Tamarindus indica) fruit juice @ 100 g/4L of water at 7 days interval.

T₃ = Neem (Azadirachta indica) leaf extract @ 0.5 kg/4L of water at 7 days interval.

T₄ = Bullock's heart (Annona reticulate) leaf extract @ 0.5 kg/4L of water at 7 days interval.

T₅ = Dodder (Cascuta reflexa) extract @ 0.5 kg/4L of water at 7 days interval.

T₆ = Oleander (Nerium oleander) leaf extract @ 0.5 kg/4L of water at 7 days interval.

T₇= Dhutra (Datura metel) leaf extract @ 0.5 kg/4L of water at 7 days interval.

T₈ = Dholkolmi (Ipomoea carnea) leaf extract @ 0.5 kg/4L of water at 7 days interval. T₉ = Control.

Preparation of plant extracts

Tamarind fruit juice: 100g ripe tamarind socked in 4L of water through overnight and before application it was mixed properly. The solid materials separated from mixture by sieve.

Neem leaf extract: 0.5 kg fresh neem leaf blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Bullock's heart leaf extract: 0.5 kg fresh bullock's heart leaf blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Dodder extract: 0.5 kg fresh dodder blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Oleander leaf extract: 0.5 kg fresh olender leaf blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Dhutora leaf extract: 0.5 kg fresh dhutora leaf blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Dholkolmi leaf extract: 0.5 kg fresh dholkolmi leaf blended by electric blender then it mixed with 4L of water. The solid materials separated from mixture by sieve.

Layout and design of experiment

The experiment comprised 9 treatments combination and laid out in RCBD with three replications. The whole field was divided into three blocks and each block consisted of 9 plots. Altogether there were 27 unit plots in each experiment and required 432m² lands. Each plot was 9m² (3m ×3m) in size. The distance between plots was 1.00m, distance between plants to plant was 50cm and that of row to row was 50cm.

Cultivation of okra

Land preparation

The selected land for the experiment was first opened on 27 March 2011 by power tiller and expose to the sun for a week. After one week the land was ploughed and cross-ploughed several times with a power tiller and laddering to obtain good tilth followed each ploughing. Weeds and stubble's were removed and the large clods were broken into smaller pieces to obtain a desirable tilth of soil for sowing of seeds.

After removal of the weeds, stubble's and dead roots, the land was leveled and the experimental plot was partitioned in to the unit plots in accordance with the design, and the edge around each unit plot was raised to check run out of the nutrients. All types of manures were applied during final land preparation as basal dose (Mohammad et al., 2016; Sheikh et al., 2025).

Manure and fertilizer application

The entire quantity of cowdung (10 ton/ha) was applied just after opening the land. Urea was applied as per treatment in each randomized plots of 9m². Triple Super Phosphate (TSP) and Muriate of Potash (MP) were applied at the rate of 100kg/ha and 150kg/ha respectively. Full dose of TSP and cowdung were applied to the soil at the final land preparation. Urea and MP were applied as side dressing (ring method) in 3 equal installments at 15, 30 and 45 days after germination.

Sowing of seeds

Seeds were sown on 28 April, 2011. In each plot, seeds were sown in rows and there were three rows in each plot. In the rows, plant to plant distance was 50 cm and row to row distance was 50 cm. the seeds were covered with fine soil by hand. The field was irrigated lightly immediately after sowing. In each plot there were 36 okra plants.

Intercultural operations

The seedlings were always-kept under close obser-vation. Necessary intercultural operations were done throughout the cropping season to obtain proper growth and development of the plants.

Thinning

When the seedlings got established, one healthy seedling in each location was kept and other seedlings were removed.

Gap filling

Dead, injured and weak seedlings were replaced by new vigor seedling from the stock on the border line of the experiment.

Weeding

Four weeding were done manually at 15, 30, 45 and 60 DAS to keep the plots free from weeds.

Irrigation

Light overhead irrigation was provided with a watering can to the plots once immediately after sowing of seed and then it was continued at 3 days interval after seedling emergence for proper growth and develop-ment of the seedlings, when the soil moisture level was very low. Wherever the plants of a plot had shown the symptoms of wilting the plots were irrigated on the same day with a hosepipe until the entire plot was properly wet.

Drainage

Stagnant water effectively drained out at the time of heavy rains.

Harvesting

As the seeds were sown in the field at times, the crops were harvested at different times. Green pods were harvested at four days interval when they attained edible stage. Green pod harvesting was started from 10 May and was continued up to 17 August, 2011.

Collection of data on yield and yield contributing character

Infestation of okra shoot & fruit by okra shoot and fruit borer was monitored during both vegetative and reproductive stages. Infested shoots and fruits were counted and recorded at 7 days intervals after observing the bores and excreta in both vegetative and reproductive stage.

Data recorded: The data on the following parameters were recorded at different time intervals as given below:

• Number of insect population (aphid, jassid, mealybug, whitefly) per plant after different treatments. Insect population data was collected early in the morning from three leaves (upper, middle and lower) of each plant and three plants from each plot. Then average value was recorded.
• Plant height at 20, 30, 40 and 50 days after transplant
• Number of leaves per plant at 20, 30, 40 and 50 days after transplant
• Number of branch per plant at 20, 30, 40 and 50 days after transplant
• Number of fruits per plant at each harvesting time
• Fruit length at different each harvesting time
• Fruit diameter at each harvesting time
• Fruit weight at different each harvesting time

Percent reduction of pest population over control

The percent reduction of pest population was cal-culated by using the following formula: 

Percent increase of plant character over control

The percent reduction of pest population was calculated by using the following formula:

Statistical analysis

The collected data on various parameters were statistically analyzed MSTATC package program. The mean for all the treatments were calculated and analyzed of variance for all the characters were performed by F-variance test. The significance of difference between the pairs of treatment mean was calculated by the Duncan Multiple Range Test (DMRT) at 5% level of probability.

The results on the effectiveness of various treatments including untreated control for the management of sucking pests of okra have been described and discussed with following sub headings:

Table 1: Incidence of aphid on infested leaf of okra under different treatments.

Effect of various treatments on incidence of aphid on okra

The incidence of aphid on infested leaf of okra under different treatments has been shown in Table 1. The data indicate that the lowest number of aphid (9.41) was observed in oleander leaf extract treated plot followed by 9.73, 9.77 and 9.80 in bullock's heart leaf extract, ripcord and dhutra leaf extract treated plots respectively having no significant difference among them. On the other hand, the highest number of aphid per infested leaf (12.45) was recorded as in untreated control plot which was statistically different from all other treatments (Table 1) and it was followed by tamarind fruit juice (10.29) and dholkolmi leaf extract (10.27) treated plots. In case of the percent reduction of number of aphid over control, the highest reduction percent (24.23 %) was recorded in oleander leaf extract treated plot and followed by Bullock's heart leaf extract (21.79 %), ripcord 10EC (21.59 %) and dhutra (21.11 %) treated plot. On the other hand, the lowest percent of reduction over control (17.23 %) was recorded in tamarind fruit juice treated plot (Table 1) followed by dholkolmi leaf extract (17.53 %), dodder extract (19.43 %) and neem leaf extract (20.82 %) treated plot which was statistically similar with other treatments in terms of reduction of number of aphid over control.

Considering the percent reduction of number of aphid over control, the best effect (24.23 %) was observed in oleander leaf extract treated plot and the lowest reduction (17.23 %) was observed in tamarind fruit juice treated plot (Table 1). This result agrees with findings who observed that extracts of neem, garlic, tobacco straw wash and a mixture of soap with kerosene reduced mustard aphid infestation and increased yield. Jayakumar (2002) also reported that aphid and leafhopper incidence on okra was minimized by spraying neem oil + garlic extract, garlic extract + chilli extract, garlic extract + cow urine and NSKE + cow urine. Most of the findings showed that neem products have best result but in the present study oleander leaf extract showed the best performance against aphid and other botanicals including neem leaf extract also showed better result over control. This difference is logical because of different ecological condition. In the experiment bullock's heart (Annona reticulate) also showed the best result which supported the findings Rosaiah (2001a) who reported that the leaf extract of Annona reticulat and Jatropa showed high effectiveness against the aphid of bhendi, petroleum ether extract of bullock's heart leave was tried against cotton aphid, A. gossypii at Tirupathi. These leaf extracts gave 88.81 to 90.06 per cent reduction in aphid population (Chitra et al., 1997).

In a column, means followed by the same letter (s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Table 2: Incidence of jassid on infested leaf of okra under different treatments.

Effect of various treatments on incidence of jassid on okra

The population of jassid per infested leaf of okra under different treatments has been shown in Table 2. The data reveal that significant differences were observed among different treatments in terms of number of jassid per infested leaf. The lowest number of jassid per infested leaf (5.62) was recorded in dhutra leaf extract treated plot followed by 5.77 in oleander leaf extract, 5.93 in bullock's heart leaf extract and 6.08 in ripcord 10EC. On the other hand, the highest number of jassid per infested leaf was 8.21 recorded in untreated control plot which was statistically different from all other treatments (Table 2) and followed by neem leaf extract (6.47) treated plot. In Table 2, 6.18 in dodder extract, 6.22 in Tamarind fruit juice and 6.35 in dholkolmi leaf extract treated plot were significantly lower than control plot but statistically similar with other treatments. In case of the percent reduction of number of jassid over control, the highest percent reduction (35.42 %) was recorded in dhutra leaf extract treated plot and followed by 29.45 % in oleander leaf extract treated plot. On the other hand, the lowest percent of reduction over control (21.30 %) was recorded in neem leaf extract (Table 2) and it was followed by dholkolmi leaf extract (22.71 %). Ripcord 10EC (26.10 %), dodder extract (23.88 %) and tamarind fruit juice (23.86 %) were significantly lower than dhutra leaf extract treated plot but statistically similar with other treatments in terms of percent reduction of jassid over control. The above result indicates that dhutra leaf extract was the best plant materials against jassid attacking okra.This result could not compare with other due to lack of appro-priate reference. However, these results contradict with the findings of Jayakumar (2002), who reported that spraying neem oil + garlic extract minimized the incidence of aphid and jassid.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of various treatments on incidence of mealy-bug on okra

The incidence of mealybug on okra under different treatments has been shown in Table 3. The data indicate that the lowest number of mealybug (0.3767) was recorded in ripcord 10EC treated plot followed by 0.4000 in dholkolmi leaf extract and 0.4033 in dhutra leaf extract treated plot having no significant differ-ence among them. On the other hand, the highest number of mealybug per leaf 1.123 was recorded in untreated control plot (Table 3) followed by (0.6367) dodder extract treated plot having significant differ-ence between them. However, no significant difference was found in bullock's heart leaf extract (0.5300), tamarind fruit juice (0.4461), oleander leaf extract (0.4467) and neem leaf extract (0.4233) treated plot. In case of the percent reduction of number of mealybug over control, the highest percent reduction (66.35 %) was recorded in ripcord 10EC treated plot followed by dholkolmi leaf extract (63.91 %), dhutra leaf extract (63.29 %) and neem leaf extract (61.60 %) treated plot having significant difference between them. On the other hand, the lowest percent of reduction over control (44.39 %) was recorded in dodder extract treated plot was statistically different from all other treatments (Table 3) followed by bullock's heart leaf extract (53.09 %) treated plot having significant difference between them. Oleander leaf extract (59.83 %) and tamarind fruit juice (60.04 %) treated plot were significantly lower than ripcord 10EC treated plot.

The above result indicates that ripcord 10EC was the best plant materials against mealybug attacking okra. This result contradicts with Chandrashekharappa (1995) who reported that neem seed carnal extract was effective against mealybug. In this experiment beside Ripcord 10EC others plant materials showed better performance over control. In terms of percent reduction it also contradict that cotton seed oil at various concentrations gave the higher mortality (>95%) of Pseudococcus hirsutus. The difference in result may be due to different ecological condition and different application procedure (Shahen et al., 2019).

Table 3: Incidence of mealybug on infested leaf of okra under different treatments.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of various treatments on incidence of whitefly on okra

The population of whitefly per infested leaf of okra was studied in relation to different treatments. Significant differences were observed among different treatments in terms of number of whitefly per infested leaf (Table 4). The data indicate that the lowest number of whitefly per infested leaf (4.07) was recorded in ripcord 10EC treated plot which was statistically insignificant with tamarind fruit juice (4.20), bullock's heart leaf extract (4.28), dodder extract (4.30) and dhutra leaf extract (4.35) treated plot. On the other hand, the highest number of whitefly per infested leaf (5.98) was recorded in untreated control plot which was statistically different from all other treatments (Table 4). In terms of number of whitefly per infested leaf no significant differ-ence was observe in dholkolmi leaf extract (4.82), neem leaf extract (4.73) and oleander leaf extract (4.60) treated plot. In case of the percent reduction of number of whitefly over control, the highest percent reduction (31.31 %) was recorded in ripcord 10EC treated plot which was statistically insignificant with tamarind fruit juice (29.50 %), bullock's heart leaf extract (28.35 %) and dodder extract (27.77 %) treated plot respectively. On the other hand, The lowest percent of reduction over control (19.43 %) was recorded in dholkolmi leaf extract treated plot was statistically significant from ripcord 10EC, tamarind fruit juice, bullock's heart leaf extract, dodder extract, dhutra leaf extract treated plot (Table 4) and it was statistically non-significant to neem leaf extract (21.10 %) and oleander leaf extract (22.85 %) treated plot.

The above result indicates that ripcord 10EC was the best plant materials against whitefly attacking okra (Table 4). However, two neem products, Neemax and Neemguard (3 ml/l) when combined with sub- lethal dose of monocrotophos (0.086%) gave effective control of nymphal and adult population of B. tabaci on cotton. It also contradict to the findings of Singh et al. (1999), spraying neem seed extract (5%) and neem oil (5%) resulted in considerable reduction of whitefly population on cotton and Ahmad et al. (1995) observed the ovipositional deterrence of neem oil against B. tabaci on cotton. In this experiment ripcord 10EC showed the best and neem leaf extract showed poor result reported that NSKE (5%) and neem oil (5%) caused 93.7 and 90.3 per cent mortality of nymphal stage of B. tabaci atseven days after spraying, respectively. B. tabaci population was suppressed effectively by neem oil. The difference in result may be due to different ecological condition, different application procedure and combination of treatment.

Effect of various treatments on plant height (cm) of okra against sucking pest infestation

A remarkable variation was observed in plant height in different treatments that was shown in Table 5. The data shown that the highest plant height (79.45 cm) was recorded in dholkolmi leaf extract followed by dodder extract (78.00 cm) and dhutra leaf extract (77.78 cm) treated plot respectively having no significant difference among them (Table 5). On the other hand, the lowest plant height was recorder as (64.89 cm) in untreated control plot, which was statistically different from all other treatments (Table 5) followed by neem leaf extract (73.00 cm) and bullock's heart leaf extract having no significant difference between them. In terms of percent increase of plant height over control, all treatments shown better result because all treatments reduce consider-able amount of sucking pest infestation.

Table 4: Incidence of whitefly on infested leaf of okra under different treatments.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

The highest increase percent of plant height (18.21 %) was recorded in dholkolmi leaf extract treated plot followed by oleander leaf extract (16.79 %), dodder extract (16.58 %), dhutra leaf extract (16.18 %) and ripcord 10EC (16.14 %) treated plot having no significant difference between them. On the other hand, The lowest percent of increase over control (11.09 %) was recorded in neem leaf extract treated plot was statistically significant from all treatments and it was statistically non-significant to bullock's heart leaf extract (12.55 %) and oleander leaf extract (22.85 %) treated plot (Table 5). The above result indicates that the best plant materials for increasing plant height against sucking pests was dholkolmi leaf extract (Table 5).

Table 5: Effect of different treatments on plant height of okra against sucking pest infestation.

In a column, means followed by the same letter (s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of different treatments on number leaves/ plant of okra against sucking pest infestation

The results on the effect of different treatments on leaf infestation caused by the sucking pests have been studied. A remarkable variation was observed in number of leaf per plant in different treatments showed in Table 6. The data shown that the height number of leaf per plant (50.56) was recorded in dholkolmi leaf extract treated plot, which was statistically significant from all treatments followed by ripcord 10EC (47.89), dhutra leaf extract (47.78) and bullock's heart leaf (47.60), respectively having no significant different among them (Table 6). On the other hand, the lowest number of leaf per plant was recorder as (40.55) in untreated control plot, which was statistically different from all other treatments (Table 6) followed by neem leaf extract (43.41), tamarind fruit juice (45.59) and oleander leaf extract (46.45) treated plot having significant difference among them. In terms of percent increase of number of leaf per plant over control the highest percent increase of number of leaf per plant (19.18 %) was recorded in dholkolmi leaf extract treated plot, which was statistically significant from all treatments followed by ripcord 10EC (15.40 %), dhutra leaf extract (15.21 %) and bullock's heart leaf extract (14.75 %) having no significant difference among them. On the other hand, the lowest percent of increase over control (6.67 %) was recorded in neem leaf extract treated plot which was statistically significant from all treatments followed by oleander leaf extract (12.06 %), tamarind fruit juice (12.45 %) and dodder extract (12.87 %) treated plots having no significant difference between them (Table 6). For percent increase of plant height over control, dholkolmi leaf extract was the best plant materials and neem leaf extract shown the least performance (Table 6). The result cannot be compare with others due to lack of reference.

Table 6: Effect of different treatments on leaf per plant of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of different treatments on number branch/ plant of okra against sucking pest infestation

The number of branch per plant at different stage of okra plant was significantly influenced by the appli-cation of different treatments. The results revealed that the height number of branch per plant (4.17) was recorded in dholkolmi leaf extract treated plot which was statistically significant from all treatments followed by ripcord 10EC (3.74) having significant difference between them (Table 7). However no significant difference was found in tamarind fruit juice (3.35), oleander leaf extract (3.35) and dodder extract (3.34) treated plot. On the other hand, the lowest number of branch per plant was recorder as (2.55) in untreated control plot, which was statistically dif-ferent from all other treatments (Table 7) followed by bullock's heart leaf extract (3.10) having significant difference between them. In terms of percent increase of number of branch per plant over control, the highest percent increase of number of branch per plant (39.17 %) was recorded in dholkolmi leaf extract treated plot which was statistically significant from all treatments followed by ripcord 10EC (31.91 %) having significant difference between them. However no significant difference was found in tamarind fruit juice (23.96 %), oleander leaf extract (23.96 %) and dodder extract (23.52 %) treated plot.. On the other hand, the lowest percent of increase over control (17.66 %) was recorded in Bullock's heart leaf extract treated plot which was statistically non-significant to dhutra leaf extract (17.87) and significantly lower from all treatments (Table 7). Considering the percent increase of number of branch per plant over control, dholkolmi leaf extract shown the best result among the all plant materials and bullock's heart leaf extract shown the least performance (Table 7). The result cannot be compare with others due to lack of reference.

Table 7: Effect of different treatments on branch per plant of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of different treatments on number of fruit per plant of okra against sucking pest infestation

The number of fruit per plant at fruiting stage of okra plant was significantly influenced by the application of different treatments. The results revealed that the height number of fruit per plant (9.83) was recorded in dhutra leaf extract treated plot, which was statistically significant from all treatments followed by bullock's heart leaf extract (8.40) and oleander leaf extract (7.83) treated plot having significant different with dhutra leaf and other treatments (Table 8). On the other hand, the lowest number of fruit per plant was recorder as (5.83) in untreated control plot, which was statistically different from all other treatments (Table 8). However no significant difference was found in neem leaf extract (6.46) and dholkolmi leaf extract (6.66) treated plot. In terms of percent increase of number of fruit per plant over control, the highest increase percent of number of fruit per plant (40.85 %) was recorded in dhutra leaf extract treated plot which was statistically significant from all treatments followed by bullock's heart leaf extract (30.70 %) having significant difference between them. 

Table 8: Effect of different treatments on fruit per plant of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

On the other hand, the lowest percent of increase over control (9.73 %) was recorded in neem leaf extract treated plot which was statistically non-significant to all treatments followed by dholkolmi leaf extract (12.57 %) having no significant difference between them (Table 8). Above results indicate that dhutra leaf extract was the best plant materials for increasing number of fruit against sucking insect pests attacking okra. The result cannot be compare with others due to lack of reference.

Effect of different treatments on fruit length (cm) of okra against sucking pest infestation

The effect of different treatments on okra fruit length against sucking insect pest's infestation has been presented in (Table 9). The result reveals that the highest fruit length (15.06 cm) was observed in tamarind fruit juice treated plots followed by (14.80 cm) and (14.58 cm) in neem leaf extract and dhol-kolmi leaf extract, respectively with no significant difference among them. Next to them, ripcord 10EC (14.53 cm), oleander leaf extract (14.25 cm), bullock's heart leaf extract (14.19 cm), dhutra leaf extract (14.17 cm), and dodder extract (14.08 cm) having no significant difference between them. The lowest fruit length of okra (12.46 cm) was recorded from control plots, which was significantly lower than all other treated plots. In terms of increase of fruit length over control, tamarind fruit juice treated plots showed the best performance by increasing (17.18 %) fruit length followed by neem leaf extract and dholkolmi leaf extract ( 15.79 and 14.49 % respectively). On the other hand, dodder extract (11.45 %) and dhutra leaf extract (12.01 %) showed the least effectiveness in increasing length of fruit (Table 9). The result cannot be compare with others due to lack of reference.

Table 9:  Effect of different treatments on fruit length (cm) per plant of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

Effect of different treatments on fruit diameter (cm) of okra against sucking pest infestation

The effect of different treatments on okra fruit diameter against sucking pest infestation has been presented in (Table 10). The data shown that the highest fruit diameter (6.60 cm) was observed in neem leaf extract treated plots followed by (6.47 cm) and (6.38 cm) in ripcord 10EC and bullock's heart leaf extract respectively with no significant difference among them. Next to them, tamarind fruit juice (6.13 cm), oleander leaf extract (6.06 cm), dodder extract (6.05cm) having no significant difference between them. The lowest fruit diameter of okra (4.61 cm) was recorded from control plots, which was significantly lower than all other treated plots and followed by dholkolmi leaf extract (5.82) and Dhutra leaf extract (5.63). In terms of increase of fruit diameter over control, neem leaf extract treated plots showed the best performance by increasing (30.09 %) fruit length followed by ripcord 10EC and bullock's heart leaf extract (28.73 % and 27.77 % respectively) having no significant difference between them. On the other hand, dhutra leaf extract (18.07 %) showed the least effectiveness in increasing diameter of fruit (Table 10). Dholkolmi leaf extract (25.11 %), Tamarind fruit juice (24.66 %), Oleander leaf extract (23.89 %) and Dodder extract (23.74%) was non-significant to each other but significant to highest and lowest value.

Table 10: Effect of different treatments on fruit diameter (cm) per plant of okra against sucking pest infestation.

Effect of various plant materials on fruit weight (g) of okra against sucking pest infestation

The effect of different treatments on okra fruit weight against sucking pest infestation has been presented in (Table 11). The data raveled that the highest fruit weight (29.33 g) was observed in tamarind fruit juice treated plots followed by (28.92 g), (28.76 g) and (28.25 g) in oleander leaf extract, dholkolmi leaf extract and ripcord 10EC, respectively with no significant difference among them. Next to them, dodder extract (27.58 g), neem leaf extract (27.41), dhutra leaf extract (27.32 g) having no significant difference between them. The lowest fruit weight of okra (20.95) was recorded from control plots, which was signi-ficantly lower than all other treated plots followed bullock's heart leaf (27.24 g) and dhutra leaf extract (27.32 g) having no significant difference between them. In terms of percent increase of fruit weight over control, tamarind fruit juice treated plots showed the best performance by increasing (28.58 %) fruit weight followed by oleander leaf extract, dholkolmi leaf extract and ripcord 10EC (27.48 %, 27.22 % and 25.60 % respectively) having no significant difference between them. 

Table 11: Effect of different treatments on fruit weight (g) per plant of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

On the other hand, bullock's heart leaf extract (23.20 %) showed the least effectiveness in increasing weight of fruit (Table 11) was significant to dhutra leaf extract (23.29 %). The result cannot be compare with others due to lack of reference.

Effect of various plant materials on yield (g) per plot of okra against sucking pest infestation

The yield per plot of okra plant was significantly influenced by the application of different treatments. The results revealed that the height yield per plot (577.7 g) was recorded in bullock's heart leaf treated plot followed by dodder extract (505.6 g), tamarind fruit juice (504.2 g), dhutra leaf extract (502.8 g) and dholkolmi leaf extract (502.0 g) treated plot (Table 12) having no significant difference between them. How-ever no significant difference was found in oleander leaf extract (473.6 g), ripcord 10EC (445.8 g) and neem leaf extract (440.0 g) treated plot. On the other hand, the lowest yield per plot was recorder as (410.0 g) in untreated control plot, which was statistically different from all other treatments (Table 12). In terms of percent increase of yield per plot over control, all treatments increase considerable amount of yield. The highest increase percent of yield per plot (40.35 %) was recorded in bullock's heart leaf treated plot, which was statistically significant from all treatments. How-ever no significant difference was found in dodder extract (32.09 %), tamarind fruit juice (31.76 %), dhutra leaf extract (31.61 %) and dholkolmi leaf extract (30.92 %) treated plot. On the other hand, the lowest percent of increase over control (24.34 %) was recorded in ripcord 10EC treated plot which was statistically non- significant to neem leaf extract (24.98 %), oleander leaf extract (28.37 %) and significantly lower from all treatments (Table 12). Considering the percent increase of yield over control, among the all treatments bullock's heart leaf extract was the best plant materials (Table 12). The result cannot be compare with others due to lack of reference.

Table 12: Effect of different treatments on yield per plot (g) of okra against sucking pest infestation.

In a column, means followed by the same letter(s) are not significantly different at 5% level of probability by Duncan's Multiple Range Test (DMRT).

The present experiment was conducted at the field laboratory of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka during the period from April to August, 2011 to find out the efficacy of different plant materials against sucking pest of okra. The treatments are comprised with seven botanical product, one synthetic chemical insecticides and one untreated control and these are T1 = Ripcord 10EC @ 1ml/L of water at 7 days interval, T2 = Tamarind fruit juice @ 100g/4L of water at 7 days interval, T3 = Neem leaf extract @ 0.5kg/4L of water at 7 days interval, T4 = Bullock's heart leaf extract @ 0.5kg/4L of water at 7 days interval, T5 = Dodder extract @ 0.5kg/4L of water at 7 days interval, T6 = Oleander leaf extract @ 0.5kg/4L of water at 7 days interval, T7 = Dhutra leaf extract @ 0.5kg/4L of water at 7 days interval, T8 = Dholkolmi leaf extract @ 0.5kg/4L of water at 7 days interval, T9 = Control. The experiment was laid out in single factor Randomized Complete Block Design (RCBD) with three replications. The lowest number of aphid per infested leaf was recorded in oleander leaf extract (9.41) treated plot followed by bullock's heart leaf extract (9.73), ripcord 10EC (9.77) and dhutra leaf extract (9.80) treated plot having no significant difference among them. The highest number of aphid per leaf (12.45) was recorded in control plot. Considering the percent reduction of number of aphid over control, oleander leaf extract gave the best result by reducing (24.23 %) aphid over control followed by bullock's heart leaf extract (21.79 %) and ripcord 10EC (21.59 %) and dhutra leaf extract (21.11 %) treated plot having no significant difference among them and tamarind fruit juice treated plot gave the lowest result by reducing (17.23 %). The lowest number of jassid per infested leaf was recorded in dhutra leaf extract (5.62) treated plot followed by oleander leaf extract (5.77), bullock's heart leaf extract (5.93) and ripcord 10EC (6.08) treated plot having no significant difference among them. The highest number of jassid per leaf (8.21) was recorded in untreated control which was statistically different from all other treatments. In case of the percent reduction of number of jassid over control, dhutra leaf extract gave the best result by reducing (35.42 %) jassid over control and neem leaf extract treated plot shown least performance by reducing (21.30 %).

The lowest number of mealybug per infested leaf was recorded in ripcord 10EC (0.3767) treated plot and followed by dholkolmi leaf extract (0.4000), dhutra leaf extract (0.4033) treated plot having no significant difference among them. The highest number of mealybug per leaf was recorded in control (1.123). Considering the percent reduction of number of mealybug over control, ripcord 10EC shown the best performance by reducing (66.35 %) and the lowest percent reduction (44.39 %) was observed in dodder extract treated plot. The lowest number of whitefly per infested leaf was recorded in ripcord 10EC (4.07) treated plot and the highest number of whitefly per leaf (5.98) was recorded in untreated control. In terms of percent reduction over control, ripcord 10EC treated plot gave the best result by reducing (31.31 %) whitefly over control and the lowest percent reduction (19.43 %) was recorded in dholkolmi leaf extract treated plot. The highest plant height was recorded in dholkolmi leaf extract (79.45 cm) treated plot and the lowest plant height was recorder as (64.89 cm) in untreated control plot. In terms of percent increase of plant height over control, the highest percent increase (18.21 %) was observed in dholkolmi leaf extract and the lowest percent increase (11.09 %) was recorded in neem leaf extract treated plot.

The height number of leaf per plant was recorded in dholkolmi leaf extract (50.56) treated plot, which was statistically significant from all treatments and the lowest number of leaf per plant was recorder as (40.55) in untreated control plot, which was statis-tically different from all other treatments. Considering the percent increase of leaf per plant over control, dholkolmi leaf extract gave the best result by increasing (19.81 %) and the lowest percent increase (6.67 %) was recorded in neem leaf extract treated plot. The height number of branch per plant was recorded in dholkolmi leaf extract (4.17) treated plot, which was statistically significant from all treatments and the lowest number of branch per plant was recor-der as (2.55) in untreated control plot. Considering the percent increase of branch per plant over control, dholkolmi leaf extract shown the best performance by increasing (39.17 %) and bullock's heart leaf extract shown the least performance by increasing the lowest percent increase (17.66 %). The highest number of fruit per plant was recorded in dhutra leaf extract (9.83) treated plot and the lowest number of fruit per plant was recorder as (5.83) in untreated control plot. Considering the percent increase of fruit per plant over control, the highest percent increase was observed in dhutra leaf extract (40.85 %) and the lowest percent increase shown in neem leaf extract (9.73 %) treated plot.

The highest fruit length was observed in tamarind fruit juice (15.06 cm) treated plots and the lowest fruit length of okra (12.46 cm) was recorded from control plots. In percent increase of fruit length per plant over control, tamarind fruit juice treated plots showed the best performance by increasing (17.18 %) fruit length. On the other hand, dodder extract (11.45 %) and dhutra leaf extract (12.01 %) showed the least effectiveness in terms of increasing length of fruit. The highest fruit diameter was observed in neem leaf extract (6.60 cm) treated plots and the lowest fruit diameter of okra (4.61 cm) was recorded from control plots. In percent increase of fruit diameter per plant over control, the best performance by neem leaf extract by increasing (30.09 %) fruit length and dhutra leaf extract (18.07 %) showed the least effectiveness in increasing diameter of fruit. The highest fruit weight was observed in tamarind fruit juice (29.33 g) treated plot and the lowest fruit weight of okra (20.95) was recorded from control plots, which was significantly lower than all other treated plots. Considering the percent increase of fruit weight per plant over control, tamarind fruit juice treated plots showed the best performance by increasing (28.58 %) fruit weight and bullock's heart leaf extract (23.20 %) showed the least effectiveness in increasing weight of fruit. The highest yield per plot was recorded in bullock's heart leaf extract (577.7 g) treated plot, which was followed by dodder extract (505.6 g), tamarind fruit juice (504.2 g), dhutra leaf extract (502.8 g) and dholkolmi leaf extract (502.0 g) treated plot having no significant difference among them and the lowest yield per plot was recorder as (410.0 g) in untreated control plot. Considering the percent increase of yield per plot over control, bullock's heart leaf extract gave the best result by increasing (40.35 %) over control and the lowest percent of increase over control (24.34 %) was recorded in ripcord 10EC treated plot.

Based on the above findings of the study it can be concluded that oleander leaf extract was the best plant material for the management of aphid population. Dhutra leaf extract showed the best performance against jassid population. Whitefly and mealybug population were minimized by using ripcord 10EC. In case of plant yield attributing character, plant height, leaf per plant, branch per can be increased by using dholkolmi leaf extract. Dhutra leaf extract was the best plant materials for increasing number of fruit per plant. Tamarind fruit juice can be used for maxi-mization of fruit weight and fruit length. For maxi-mum fruit diameter per plant neem leaf extract showed the best result. Finally bullock's heart leaf extract showed the best result in terms of increasing yield per plot among the all plant materials. Considering the findings of the study the following recommendations can be drawn:

• Oleander and dhutra leaf extract may be used for the management of sucking insect pests of okra.
• Further intensive studies based on different doses of different plant materials should be done.
• More chemicals and botanicals should be included in further elaborative research for controlling sucking insect pest okra.

The present experiment was conducted at the field laboratory of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka during the period from April to August, 2011 to find out the efficacy of different plant materials against sucking pest of okra. The treatments are comprised with seven botanical product, one synthetic chemical insecticides and one untreated control and these are T1 = Ripcord 10EC @ 1ml/L of water at 7 days interval, T2 = Tamarind fruit juice @ 100g/4L of water at 7 days interval, T3 = Neem leaf extract @ 0.5kg/4L of water at 7 days interval, T4 = Bullock's heart leaf extract @ 0.5kg/4L of water at 7 days interval, T5 = Dodder extract @ 0.5kg/4L of water at 7 days interval, T6 = Oleander leaf extract @ 0.5kg/4L of water at 7 days interval, T7 = Dhutra leaf extract @ 0.5kg/4L of water at 7 days interval, T8 = Dholkolmi leaf extract @ 0.5kg/4L of water at 7 days interval, T9 = Control. The experiment was laid out in single factor Randomized Complete Block Design (RCBD) with three replications. The lowest number of aphid per infested leaf was recorded in oleander leaf extract (9.41) treated plot followed by bullock's heart leaf extract (9.73), ripcord 10EC (9.77) and dhutra leaf extract (9.80) treated plot having no significant difference among them. The highest number of aphid per leaf (12.45) was recorded in control plot. Considering the percent reduction of number of aphid over control, oleander leaf extract gave the best result by reducing (24.23 %) aphid over control followed by bullock's heart leaf extract (21.79 %) and ripcord 10EC (21.59 %) and dhutra leaf extract (21.11 %) treated plot having no significant difference among them and tamarind fruit juice treated plot gave the lowest result by reducing (17.23 %). The lowest number of jassid per infested leaf was recorded in dhutra leaf extract (5.62) treated plot followed by oleander leaf extract (5.77), bullock's heart leaf extract (5.93) and ripcord 10EC (6.08) treated plot having no significant difference among them. The highest number of jassid per leaf (8.21) was recorded in untreated control which was statistically different from all other treatments. In case of the percent reduction of number of jassid over control, dhutra leaf extract gave the best result by reducing (35.42 %) jassid over control and neem leaf extract treated plot shown least performance by reducing (21.30 %).

The lowest number of mealybug per infested leaf was recorded in ripcord 10EC (0.3767) treated plot and followed by dholkolmi leaf extract (0.4000), dhutra leaf extract (0.4033) treated plot having no significant difference among them. The highest number of mealybug per leaf was recorded in control (1.123). Considering the percent reduction of number of mealybug over control, ripcord 10EC shown the best performance by reducing (66.35 %) and the lowest percent reduction (44.39 %) was observed in dodder extract treated plot. The lowest number of whitefly per infested leaf was recorded in ripcord 10EC (4.07) treated plot and the highest number of whitefly per leaf (5.98) was recorded in untreated control. In terms of percent reduction over control, ripcord 10EC treated plot gave the best result by reducing (31.31 %) whitefly over control and the lowest percent reduction (19.43 %) was recorded in dholkolmi leaf extract treated plot. The highest plant height was recorded in dholkolmi leaf extract (79.45 cm) treated plot and the lowest plant height was recorder as (64.89 cm) in untreated control plot. In terms of percent increase of plant height over control, the highest percent increase (18.21 %) was observed in dholkolmi leaf extract and the lowest percent increase (11.09 %) was recorded in neem leaf extract treated plot.

The height number of leaf per plant was recorded in dholkolmi leaf extract (50.56) treated plot, which was statistically significant from all treatments and the lowest number of leaf per plant was recorder as (40.55) in untreated control plot, which was statis-tically different from all other treatments. Considering the percent increase of leaf per plant over control, dholkolmi leaf extract gave the best result by increasing (19.81 %) and the lowest percent increase (6.67 %) was recorded in neem leaf extract treated plot. The height number of branch per plant was recorded in dholkolmi leaf extract (4.17) treated plot, which was statistically significant from all treatments and the lowest number of branch per plant was recor-der as (2.55) in untreated control plot. Considering the percent increase of branch per plant over control, dholkolmi leaf extract shown the best performance by increasing (39.17 %) and bullock's heart leaf extract shown the least performance by increasing the lowest percent increase (17.66 %). The highest number of fruit per plant was recorded in dhutra leaf extract (9.83) treated plot and the lowest number of fruit per plant was recorder as (5.83) in untreated control plot. Considering the percent increase of fruit per plant over control, the highest percent increase was observed in dhutra leaf extract (40.85 %) and the lowest percent increase shown in neem leaf extract (9.73 %) treated plot.

The highest fruit length was observed in tamarind fruit juice (15.06 cm) treated plots and the lowest fruit length of okra (12.46 cm) was recorded from control plots. In percent increase of fruit length per plant over control, tamarind fruit juice treated plots showed the best performance by increasing (17.18 %) fruit length. On the other hand, dodder extract (11.45 %) and dhutra leaf extract (12.01 %) showed the least effectiveness in terms of increasing length of fruit. The highest fruit diameter was observed in neem leaf extract (6.60 cm) treated plots and the lowest fruit diameter of okra (4.61 cm) was recorded from control plots. In percent increase of fruit diameter per plant over control, the best performance by neem leaf extract by increasing (30.09 %) fruit length and dhutra leaf extract (18.07 %) showed the least effectiveness in increasing diameter of fruit. The highest fruit weight was observed in tamarind fruit juice (29.33 g) treated plot and the lowest fruit weight of okra (20.95) was recorded from control plots, which was significantly lower than all other treated plots. Considering the percent increase of fruit weight per plant over control, tamarind fruit juice treated plots showed the best performance by increasing (28.58 %) fruit weight and bullock's heart leaf extract (23.20 %) showed the least effectiveness in increasing weight of fruit. The highest yield per plot was recorded in bullock's heart leaf extract (577.7 g) treated plot, which was followed by dodder extract (505.6 g), tamarind fruit juice (504.2 g), dhutra leaf extract (502.8 g) and dholkolmi leaf extract (502.0 g) treated plot having no significant difference among them and the lowest yield per plot was recorder as (410.0 g) in untreated control plot. Considering the percent increase of yield per plot over control, bullock's heart leaf extract gave the best result by increasing (40.35 %) over control and the lowest percent of increase over control (24.34 %) was recorded in ripcord 10EC treated plot.

Based on the above findings of the study it can be concluded that oleander leaf extract was the best plant material for the management of aphid population. Dhutra leaf extract showed the best performance against jassid population. Whitefly and mealybug population were minimized by using ripcord 10EC. In case of plant yield attributing character, plant height, leaf per plant, branch per can be increased by using dholkolmi leaf extract. Dhutra leaf extract was the best plant materials for increasing number of fruit per plant. Tamarind fruit juice can be used for maxi-mization of fruit weight and fruit length. For maxi-mum fruit diameter per plant neem leaf extract showed the best result. Finally bullock's heart leaf extract showed the best result in terms of increasing yield per plot among the all plant materials. Considering the findings of the study the following recommendations can be drawn:

• Oleander and dhutra leaf extract may be used for the management of sucking insect pests of okra.
• Further intensive studies based on different doses of different plant materials should be done.
• More chemicals and botanicals should be included in further elaborative research for controlling sucking insect pest okra.

We acknowledges to Mr. Md. Shakhawat Hossain for his kind support in conducting our whole research activities. 

There is no conflict of interest.