Lecanicillium lecanii, whitefly, aphid, bio-insecticides, field efficacy, integrated pest management.

Okra (Abelmoschus esculentus L.) is a widely grown vegetable crop in tropical and subtropical regions, for its nutritional and economic importance. However, its cultivation is significantly hindered by a range of insect pests that adversely affect both yield and quality parameters. More than 70 insect species are known to infest okra (Sahu et al., 2024), among the sucking pest complex comprising aphids (Aphis gossypii Glov.), leafhoppers (Amrasca biguttula Ishida) and whiteflies (Bemisia tabaci Genn.) poses the greatest economic threat (Pawar et al., 2023). These pests feed by extracting sap from the phloem tissues, leading to leaf curling, stunted plant growth, diminished photosynthetic efficiency, and considerable yield losses, which have been estimated at up to 17.46% (Singh et al., 2023; Rajwade et al., 2023).

Indian mustard (Brassica juncea L.), an important oilseed crop cultivated extensively in India, also experiences substantial yield reductions due to insect pest infestations, particularly during the vegetative and reproductive phases. Key insect pests affecting mustard include aphids (Lipaphis erysimi, Brevicoryne brassicae and Myzus persicae), sawflies (Athalia lugens proxima), leaf miners (Chromatomyia horticola), painted bugs (Bagrada hilaris), flea beetles (Phyllotreta cruciferae), and several lepidopteran defoliators such as the diamondback moth (Plutella xylostella), pod borer (Crocidolomia binotalis), hairy caterpillar (Spilosoma obliqua), and cabbage butterfly (Pieris brassicae). Among these, L. erysimi is recognized as the most destructive, with infestations beginning at the early vegetative stage and continuing through pod development (Patel et al., 2019). These aphids colonize tender plant parts and feed on phloem sap, resulting in leaf curling, crinkling, stunting, and significant losses in seed yield and oil content. Reported yield losses due to mustard aphids range between 35.4% and 91.3%, depending on varietal susceptibility and environmental conditions (Singh et al., 2023).

Although chemical insecticides such as Dimethoate 30EC and Imidacloprid 17.8SL have shown high efficacy against mustard aphids (Kumar et al., 2020; Mishra and Singh 2019), their extensive and indiscriminate use has led to multiple adverse effects. These include the development of pest resistance, resurgence of secondary pests, environmental pollution, pesticide residues in food products, and harmful impacts on non-target organisms, including pollinators and natural enemies. In response to these challenges, the use of entomopathogenic fungi (EPF) as biological control agents is gaining attention as a sustainable and eco-friendly alternative. EPF are known to infect and kill a broad spectrum of insect pests and they are compatible with integrated pest management (IPM) strategies due to their environmental safety and target specificity (Nirmalkar et al., 2025). The present study aims to evaluate the field efficacy of different formulations of entomopathogenic fungi and conventional insecticides against Bemisia tabaci in okra and Lipaphis erysimi in mustard, with the objective of identifying effective, sustainable, and environmentally sound pest management options.

A field experiment was laid out at Barrister Thakur Chhedilal, College of Agriculture and Research Station, Bilaspur (Latitude 22.078642 and Longitude 82.152328) during Kharif 2022-2023 in randomized block design to assess the field efficacy of most virulent isolate of Lecanicillium lecanii against Okra Whitefly (Bemisia tabaci) and Mustard Aphid (Lipaphis erysimi) under natural field condition. The cultivars okra variety Green wonder F1 and mustard variety  Pawan were grown in plot size of 3 × 12m and respectively with proper spacing each treatment. Good agronomic practice was followed during experiments. 

Treatment details.

Okra variety Green wonder F1 was sown of 3 × 12 cm at spacing in last week of June. Standard horticultural practices were followed during experiment. All required liquid formulations were prepared in PDA broth. Insecticides Imidacloprid 17.8% SL was used as standard check and only water used for spray in control plot. Observation on whiteflies and yellow vein mosaic virus was recorded one day before and 3rd , 7th and 10th days after spraying on five randomly selected plants covering three leaves, one each from top, middle and bottom portion of the plant. The observation on population density of whitefly (Bemisia tabaci) recorded on 30th and 45th days after sowing on three top, middle and bottom leaves of 5 designated plants, the percent reduction over control worked out using modified Abbot’s formula given by (Fleming and Ratnakaran 1985).

 P = 100 × 1 – (Ta × Cb) (Tb × Ca)

Where, P = Percentage population reduction over control 

Ta = Population in treatment after spray

Ca = Population in control after spray 

Tb = Population in treatment before spray

Cb = Population in control before spray

An observation was taken from 10cm top apical central shoot of inflorescence from 5 randomly selected plants of each plot. Both pre-treatment and post-treatment observation was taken for mustard aphid. Post-treatment observations were recorded after 3rd, 5th and 10th days of spray. In case of pre-treatment observation, it was taken 24 hours before spraying (Kafle, 2015). Percentage of population reduction over control was calculated using the modified Abbots formula as given by Fleming and Retnakaran (1985).

 PROC = [1-{(Ta × Cb) / (Tb × Ca)}] ×100

Was taken as the pre-treatment population for succeeding spray

Tb = Population in treatment before spray 

Ta = Population in treatment after sprays

 Cb = Population in control before spray

 Ca = Population in control after spray

Efficacy of Lecanicillium lecanii against whitefly (Bemisia tabaci) of Okra. Field efficacy of different formulation of entomopathogenic fungi and their combination and standard check insecticide were evaluated under natural field condition and observations was recorded at 3rd , 7th and 10th DAS, leaf infestation of white fly was recorded before spray and found statistically non-significant.

Before spray. Before spray no. of whitefly was recorded and found statistically non-significant and leaf infestation ranged from 8.17% to 9.43%.that means in all treatment the population of whitefly was almost equal.

Population of whitefly and percent reduction. Data presented on Table 1 shown the mean no. of whitefly leaf infestation was recorded maximum (6.33-3leaves) in T4 - L. lecanii (Ll2)-1.5% followed by T1- L. lecanii (Ll1) -1.5% (6.10-3leaves),  and T5 - (L. lecanii (Ll2)- 5%  (6.00-3leaves), while least population density was recorded in T11 – (Imidacloprid 17.8% SL ) (2.82-3leaves). Similarly maximum mean population no. of okra whitefly leaf infestation was found in 3rd DAS (5.81-3leaves) followed by 7th DAS (5.32-3leaves) and least no. of whitefly (4.42-3leaves) was recorded in 10th DAS.

 Data disclose from Table 1 that the mean percent reduction of leaf  infestation over control was recorded maximum 67.75% at standard check   treatment T11 - Imidacloprid 17.8% SL followed by T6 - L. lecanii (Ll2) - 10% (62.45%) and T3 - L. lecanii (Ll1) - 10% (57.55%) while, least percent reduction of leaf infestation was recorded at T4 - L. lecanii (Ll2) (28.54%). Among the entomopathogen the mean percent reduction of leaf infestation was found maximum in T6 - L. lecanii (Ll2) -10% (62.45%). Percent reduction of leaf infestation was gradually increases from 27.32% to 40.72% and 55.69% third, seventh, and ten DAS, respectively. 

3rd DAS population and percent reduction. The data presented in Table 1 shown the maximum no. of okra whitefly (7.33-3leaves) leaf  infestation was recorded 3rd day after spray in  T4 - L. lecanii (Ll2) -1.5%  followed by  T1 - L. lecanii (Ll1) - 1.5% (7.10-3leaves), and T5 - (L. lecanii (Ll2) - 5% (7.00-3leaves), and least no. of whitefly (3.03-3leaves) was recorded in T11 - Imidacloprid 17.8% SL (3.03-3leaves) respectively T3 and T6 found at par with each other.

Data on percent reduction of whitefly infestation was recorded 3rd days after spray from different treatments. All treatments showed significant effect to control the whitefly among the different treatments over untreated control. Table 1 revealed that after 3rd days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment and recorded 61.42% reduction over control  treatments T6 -L. lecanii (Ll2) - 10% (57.92%) was the next effective and significantly superior over control treatments i.e. T3 - L. lecanii 10% (49.17%), T9 - L. lecanii 50%+ Metarhizium  anisopliae  50% (45.43%), T10 - L. lecanii 50% + Bacillus thuringiensis  50% (43.62%), treatments for were also found significantly effective controlling whitefly population. Although T4 - L. lecanii (Ll2) - 1.5% (26.67%) was least effective compare to other treatments.

7th DAS population and percent reduction. The data presented in Table 1 shown the maximum no. (6.33-3leaves) of okra whitefly leaf  infestation was recorded 7th day  after spray  in  T4 - L. lecanii (Ll2) - 1.5%  followed by  T1- L. lecanii (Ll1) -1.5%  (6.10-3leaves), T5 - L. lecanii (Ll2) - 5% (6.00-3leaves), and least no of whitefly population was recorded in T11 -Imidacloprid 17.8% SL (3.43-3leaves), respectively treatments T3, T6, T8, T9 and T10 at par with each other.

Data on percent reduction of whitefly infestation was recorded 7th days after spray from different treatments. All treatments showed significant effect to control the whitefly among the different treatments over untreated control. Table 1 revealed that after 7th days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment and recorded 61.85% reduction over control. T6 - L. lecanii (Ll2) -10% (54.44%) was the next best effective and significantly superior over control. Treatments i.e. T3 - L. lecanii (Ll1) -10% (54.22%), T8 - L. lecanii 50%+ Beauveria bassiana 50% (52.97%), T9 - L. lecanii 50%+ Metarhizium anisopliae 50% (49.63%), treatments for were also found significantly effective controlling whitefly population. Although T4 - L. lecanii (Ll2) - 1.5% (29.96%) was least effective compare to other treatments.

10th DAS population and percent reduction. The data presented in Table 1 shown the maximum no. (5.33-3leaves) of okra whitefly leaf  infestation was recorded 10th day  after spray  in T4 - L. lecanii (Ll2) -1.5% followed by  T1 - L. lecanii (Ll1) -1.5% (5.10-3leaves), T5 - L. lecanii (Ll2) - 5% (5.00-3leaves), and least no of whitefly was recorded in T11 - Imidacloprid 17.8% SL (2.00-3leaves), respectively T3, T6,T7, T8 T9 and T10 found at par with each other.

 Data on percent reduction of whitefly infestation was recorded at 10th days after spray from different treatments. All treatments showed significant effect to control the whitefly among the different treatments over untreated control. Table 1 revealed that after 10th days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment except T6 and recorded 80.00% reduction over control. Followed by T6 - L. lecanii (Ll2) - 10% (75.00%) was the next effective and significantly superior over control. Treatments i.e. T3 - L. lecanii 10% (69.33%), T8 -L. lecanii 50%+Beauveria bassiana 50% (67.00%), T9 - L. lecanii 50% +Metarhizium anisopliae 50% (61.00%), and T10 - L. lecanii 50%+ Bacillus thuringiensis 50% (60.00%), treatments for were also found significantly effective controlling aphid population. Treatments T6 and T3, T3 and T8, T8, T9 and T10 found at par with each other’s means this treatment showed equally effective against white fly population. Although T4 - L. lecanii (Ll2) -1.5% (46.67%) was least effective compare to other treatments.

Similar trends were also found by Urkude et al. (2024) that  The highest percent reduction of leaf infestation 85.66% recorded by Imidachloprid 17.8% SL + L. lecanii 50% and among bio-pesticide highest reduction observed in treatment Beauveria bassiana 50% + L. lecanii 50% (76.18%) against whitefly of moongbean. Other workers also works on different insects pests using L. lecanii, combination of bio-pesticides and insecticides Verma et al. (2023) works on field efficacy of L. lecanii against leaf folder and rice stem borer in Rajeshwari and Zinco rice and find the highest percent reduction of leaf infestation 98.7 % recorded by Indoxacarb and Novaluron. Among bio-pesticide highest reduction observed in treatment Beauvaria bassiana-10% (84.9%) followed by L. lecanii-10% (81.2%)

Similar results also find many works i.e. Sarkar et al. (2016); Hemadri et al. (2016) that evaluate the efficacy of different bio-pesticides against sucking pests of okra. The treatments viz., Lecanicillium lecanii and Imidacloprid 17.8% SL. Among them best performance of insecticides against whitefly was recorded in Imidacloprid treated plots with lowest mean population of whitefly (3.91 whitefly/15 leaves) followed by karanjin (4.16 whitefly/15 leaves). Similar result also found by Janghel and Rajput (2013); Halder et al. (2021) that the efficacy of L. lecanii against whitefly (Bemisia tabaci). Maximum reduction was recorded in V. lecanii 84.20% followed by M. anisopliae, 82.91% whitefly population reduction. 

Efficacy of Lecanicillium lecanii against Aphid (Lipaphis erysimi) of Mustard. Field efficacy of different formulation of entomopathogenic fungi and their combination and standard check insecticide were evaluated under natural field condition and observations was recorded at 3rd, 5th and 10th DAS leaf infestation of aphid was recorded before spray infestation ranges from 28.00 to 28.87.Population density of mustard aphid was recorded before spray and found statistically non-significant and infestation ranged from 28.00% to 28.87%.

Population of Aphid and percent reduction.  Data presented on Table 2 shown the mean population density of mustard aphid infestation was recorded maximum (27.84%) in T4 - L. lecanii (Ll2)-1.5% followed by T1 - L. lecanii (Ll1) - 1.5% and (26.73%), T5 - L. lecanii (Ll2)- 5%  (25.11%), and least population density (9.62%) was recorded in T11 - (Imidacloprid 17.8% SL), all the other treatment were showed significant different with each other. Similarly maximum mean population density of mustard aphid infestation was found in 3rd DAS (22.13) followed by 5th DAS (19.69) and least population density (18.06) were recorded in 10th DAS. Data disclose from table that the mean percent reduction over control was recorded maximum 70.41 % at standard check treatment T11-Imidachloprid 17.8% SL followed by T6 - L. lecanii (Ll2) -10% (64.08%) and T3 - L. lecanii (Ll1) -10% (56.68%) while, least percent reduction over control was recorded 12.86% at  T4- L. lecanii (Ll2) - 1.5%. Among the entomopathogen the mean percent reduction over control was found maximum at T6 - L. lecanii (Ll2) -10% (64.08%). Percent reduction was gradually increases from 28.90% to 35.99% and 46.37% at third, fifth and ten DAS, respectively. 

3rd DAS population and percent reduction. The data presented in Table 2 that the population density of mustard aphid infestation was recorded at 3rd days after spray and found maximum (29.07%) in T4- L. lecanii (Ll2) -1.5% followed by T1- L. lecanii (Ll1) -1.5% and (27.40%), T5 - L. lecanii (Ll2) - 5% (26.00%), and least no. of whitefly was recorded in T11 - Imidacloprid 17.8% SL (15.07%). respectively T3, T6, T8, and T11 found at par with each other.

Data on percent reduction of aphid infestation was recorded 3rd days after spray from different treatments. All treatments showed significant effect to control the aphid population among the different treatments over untreated control. Table 2 revealed that after 3rd days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment expect T9 - (52.46%) and recorded 55.15%  reduction over control. T6 - L. lecanii (Ll2) 10% (51.01%) was the next effective by treatments T9 - (52.46%) and significantly superior over control. Treatments T9 and T6  showed  significantly at par with each other. treatments i.e. T3 - L. lecanii (Ll2) - 10% (40.79%), T9 - L. lecanii 50% + Metarhizium anisopliae  50%  (52.46%), and T8 -  L. lecanii 50% + Beauveria bassiana 50% (46.90%), were also found significantly effective controlling aphid population over control. Although T4- L. lecanii 1.5% (7.46%) was least effective compare to other treatments.

5th DAS population and percent reduction. The data presented in Table 2 that the population density of mustard aphid infestation was recorded at 5th days after spray and found maximum (28.07%) in T4 - L. lecanii (Ll2) -1.5% followed by T1 - L. lecanii (Ll1) -1.5% (27.07%), and T5 - L. lecanii (Ll2) - 5% (25.00%),while least population density was recorded in T11 - Imidacloprid 17.8% SL (8.80%). respectively T3 and T6  found at par with each other

Data on percent reduction of aphid infestation was recorded 5th days after spray from different treatments. All treatments showed significant effect to control the aphid among the different treatments over untreated control. Table 2 revealed that after 5th days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment and recorded 71.01% reduction over control. T6 - L. lecanii (Ll2) 10% (6.06%) was the next best effective treatments and significantly superior over control. Treatments i.e T3 - L. lecanii (Ll2) - 10% (59.55%), T9 - L. lecanii 50%+ Metarhizium anisopliae 50% (51.65%), and T8 - L. lecanii 50% + Beauveria bassiana 50% (45.25%), were also found significantly effective controlling aphid population. Although T4 - L. lecanii (Ll2)-1.5% (7.48%) was least effective compare to other treatments. All treatments showed significantly differ with each other.

10th DAS population and percent reduction. The data presented in Table 2 that the population density of mustard aphid infestation was recorded at 10th days after spray and found maximum (26.40%) in T4 - L. lecanii (Ll2) -1.5% followed by T1 - L. lecanii (Ll1) -1.5% (25.73%), and T5 - L. lecanii (Ll2) - 5% (24.33%), while least population density was recorded in T11- Imidacloprid 17.8% SL  (5.00%). Respectively T6 found at par with T11.

Data on percent reduction of mustard aphid infestation was recorded at 10th days after spray from different treatments. All treatments showed significant effect to control the mustard aphid among the different treatments over untreated control. Table 2 revealed that after 10th days of spray the standard check insecticide Imidacloprid 17.8% SL was found superior over all treatment and significantly differ with all other treatment and recorded 85.08% reduction over control followed by T6 - L. lecanii (Ll2) 10% (76.18%) was significantly at par with each other. T3 - L. lecanii (Ll1) - 10% (70.32%) was the next best effective and significantly superior over control. Treatments i.e. T9 - L. lecanii 50% + Metarhizium anisopliae 50% (59.45%), T8 - L. lecanii 50% + Beauveria bassiana 50% (57.15%), T7 - L. lecanii 50%+ Paceliomyces 50% (51.54%), and T10 - L .lecanii 50% + Bacillus thuringiensis 50% (48.43%) were also found significantly  effective treatments for controlling aphid population. Although T4- L. lecanii (Ll2) - 1.5% (23.64%) was least effective compare to other treatments. T9 and T8, T8 and T7, T7 and T10 showed non significant differ with each other, that means this treatment showed at par with each other.

Various researchers worked on the entomopathogenic fungi against the mustard aphid (Lipaphis erysimi) and found that Verticillium lecanii was effective in controlling the aphid population by 75.79% researchers Singh et al. (2008), Parmar et al. (2008); Janu et al. (2011); Kafle (2015); Kekan et al. (2022) also find similar trends of results.

Table 1: Efficacy of Lecanicillium lecanii against whitefly (Bemisia tabaci) of Okra.

Data given in parenthesis shows arcsine percentage transformation DAS- Days after spray; BS- Before spray; NS –non significance

Table 2: Efficacy of Lecanicillium lecanii against Aphid (Lipaphis erysimi) of Mustard.

Data given in parenthesis shows arcsine percentage transformation DAS- Days after spray; BS- Before spray; NS –non significance

On the basis of present study we concluded that Imidacloprid 17.8% SL were found superior treatment to reduced the white fly and aphid population (80% and 85.08%), respectively and   among the EPF and their combination treatment T6 – L. lecanii 10% concentration observed best treatment to reduced the population 75% and 76.18% at 10th DAS for whitefly and mustard aphid, respectively.

— Large scale screening of soil sample and to collect insect’s cadavers from different pest of Chhattisgarh.

— Molecular identification of isolated pathogens.

— Different physical characterization was needed to know the difference among the pathogens.

Anjali Shandilya, Vinod Kumar Nirmalkar, R.K.S. Tiwari  and Yaspal Singh Nirala  (2025). To Evaluate the Potential Isolates of L. lecanii Against Whitefly (Bemisia tabaci) and Aphid (Lipaphis erysimi) under Natural Field Condition. Biological Forum, 17(5): 134-139.