Efficacy of New Chemical Insecticides against Cabbage Aphids, Brevicoryne brassicae L. (Aphididae: Homoptera) in West Shoa of Ethiopia

Onion thrips pose a significant threat to onion crops worldwide through their feeding habits, which can lead to visible damage and potential yield loss. ‌This research aimed to investigate the effects of chemical and non-chemical insecticides on the management of onion thrips. This experimental study was conducted at the Faculty of Agriculture, Kabul University, to evaluate the efficacy of different chemical insecticides, a botanical insecticide, attractive plant, and intercropping for the management of onion thrips (Thrips tabaci) (Thysanoptera; Thripidae) on onion crops in 2023. Seven treatments were applied with three replications in a randomized complete block design. The first data collection occurred on July 12, 24 hours before the application of insecticides. Subsequent data were recorded 24 hours, 72 hours, and 7 days after each spray application. Three chemical insecticides were tested: carbaryl (Sevin® 85% WP) at a rate of 650 g/hectare, cyhalothrin (2.5% EC) at a rate of 550 ml/hectare, and cypermethrin (10% EC) at a rate of 400 ml/hectare. Additionally, a botanical insecticide derived from Melia azedarach (water extract of seeds) was applied at a rate of 12 L/hectare. After three applications, carbaryl showed significant efficacy compared to the other two chemical insecticides, while the botanical insecticide did not yield significant results. Attractive plants and intercropping demonstrated significant results when the leaves of the onions began to harden.

Cabbage is Ethiopia's second most significant vegetable crop after red pepper (Capsicum spp), although its yield and yield components are influenced by a variety of factors, including cabbage aphids, which are a major pests in most of Ethiopia's cabbage-growing areas. This study was conducted to evaluate a newly introduced chemical insecticide (Kanthion 50% E.C), and locally available botanicals. Each treatment was replicated three times and the entire setup was arranged in a randomized complete block design (RCBD) under field conditions. In the field, among the botanicals tested, N. tabacum, A. sativum, and lemon extract resulted in the highest percentage of nymphs and adult mortality greater than 65% within three days after application. In the field, non-treated control plants showed low yield as compared to the chemical, and botanical insecticide. The highest fresh weight (3.01 kg) was obtained from plants treated with Kanthion 50% E.C. This study indicates that Kanthion 50% E.C, N. tabacum, A. sativum, and Citrus limon could be recommended as an alternative management option against Brevicoryne brassicae (L) under field conditions.

Diamondback moth, Plutella xylostella (L.) is the most devastating pest in late winter in cabbage (Brassica oleracea var. capitata L.). Pesticides are the common pest management practices to manage the crucifer pests. These practices are not sustainable and ecofriendly. Hence, a field experiment was conducted to evaluate the efficacy of chemical, botanicals and biological insecticides to develop safer and more effective insecticides for the diamondback moth, in cabbage during winter season 2018-19. The experiment was laid in a randomized block design (RCBD) with four replication and five treatments viz. i) Emamectin benzoate 5SG @ 0.4 gm/l, ii) Neemix (Azadirachtin 300 ppm) @ 2 ml/l, iii) Metarhizium anisopliae @ 2 ml/l, iv) Beauveri abassiana @ 2 ml/l and v) control (untreated). Standard recommended agronomic practices were followed in field to ensure better crop growth. The maximum reduction of P. xylostella larval population over untreated control was recorded in Emamectin benzoate 5 SG (95%) and Neemix (95%) sprayed field. Bio-pesticides such as M. anisopliae and B. bassiana were effective only after the first spray with maximum efficacy of (76%) and (65%), respectively, and decreased efficacy in the second and third sprays. Both yields with the least number of damaged leaves and maximum net profit was recorded in Emamectin benzoate sprayed plots with a higher benefit-cost ratio of (3.47), which was followed by M. anisopliae (2.96) and Neemix (2.92) treatments, respectively. Emamectin benzoate 5 SG and Neemix are effective and safe insecticides in controlling diamondback moth in cabbage crops and are viable options for integrated management of P. xylostella.

Aqueous extract of Melia azedarach seeds were tested against cabbage aphid, Brevicoryne brassicae, and its predator Coccinella septempunctata in a cabbage field. The field experiment was conducted at Bridge to Israel children village farm, around the vicinity of Tewodros campus, University of Gondar, where the cabbage was grown fully organically. A field experiment was started in the middle of April 2011 and completed at the end of May 2011. The experiment was conducted in a randomised block design (RBD). For the field trial, a total of 12 plots were prepared with 1 m2 area for data collection. The powdered M. azedarach seeds were used to prepare 5% concentration of aqueous solution and sprayed. Before spraying, percentage of aphid infestation was recorded from the control plot and the experimental plot. The average percentage of cabbage infestation in the control plot was 72% and in the experimental plot before treatment was 80.85%. The percentage reduction of aphid population was 19.06% after the first spraying. However, maximum percentage reduction of 86.5% was recorded after the completion of six-week treatment. The overall percentage reduction increased proportionately from the first to sixth week. The number of predator population was reduced and the reduction was not statistically significant (p > 0.05). The present study proved that Melia seed extracts were effective against cabbage aphids under field condition. Further, it is evident that the beneficial interaction between botanical extracts and biological control organism in the field showed safety to natural enemies. In conclusion, Melia seed extract can be useful for small-scale farmers to protect their cabbage crop against cabbage aphid, B. brassicae.

Cabbage (Brassica oleracea L.) the second most important vegetable crop in Ethiopia, but cabbage aphid (Brevicoryne brassicae L.) is the main challenge for its production. The aim of the present study was, therefore, to investigate insecticidal potential aqueous extracts of Melia azedarach, Allium sativum and their combination at 5% and 10%, and 15%w/v against cabbage aphid under laboratory and field condition. Dimethoate 40% EC and distilled water were used as a positive and negative control respectively. Mortality was observed, counted after 24, 48 and 72 h exposure both in the laboratory and field conditions. The result showed that the extracts of almost all botanicals at 15% w/v concentration caused the highest (100%) toxicity effect at the end of three days. In conclusion, based on this study M. azedarach, A. sativum aqueous extracts could serve as cabbage crop protectant from can cabbage aphid (Brevicoryne brassicae for smallholder farmers.

Cabbage aphid (Brevicoryne brassicae L.) is an important pest of cabbage which reduces the yield and quality of the cabbage head. Farmers haven been using chemical pesticides to manage them but unfortunately these practices are toxic for human health, biodiversity and the environment. The study was conducted to test the efficacy of different bio-rational insecticides along with the chemical insecticide. ‘Green Coronet’ cabbage variety was used and the field experiment was laid out in the experimental farm of Agriculture and Forestry University (AFU), Rampur, Chitwan during the winter season of 2014. The Experiment was designed in randomized complete block design with having 7 treatments (bio-rational insecticides with chemical and control) and 3 replications. Plot size was 5.76 m2 (2.4m×2.4m) and spacing of 1 m was maintained between each blocks and plots. Field experiment showed that the highest reduction of cabbage aphid was obtained in Dimethoate (30 EC) treated plot followed by Derisom treated plot. The highest yield of cabbage head was obtained in Dimethoate treated plots (66.47 mt/ha) which was significantly at par with the Derisom (58.79 mt/ ha) treated plots. The yield for other treated plots were 47.60 mt/ha for Margosom, 43.77 mt/ha for Verticillium, 41.63 mt/ ha for Cow urine, 36.77 mt/ ha for Spinosad and control (33.45 mt/ ha) in terms of cabbage head yield. And, at the same time, natural enemies’ population was significantly lower to Dimethoate treated plots compared to bio-rational insecticides. Thus, Derisom (Derris based botanical) might be the best viable alternative in eco-friendly management of cabbage aphid considering cabbage head yield and protection of natural enemies. It was also evident from the research that Margosom (Neem based botanical) was found beneficial not only to conserve natural enemies in the cabbage field but also to minimize cabbage aphid population.

The study was conducted to evaluate the effectiveness of chemical and botanical insecticides against major cabbage insects at farmer field, District Dadu, Sindh during September-December 2023. Green Light” variety was sown in the first week of September, and the nursery was transplanted into the field during the first week of October. Seven treatments were applied including control viz., 10% Tobacco leaves extract, 10% Chinaberry fruit extract, 10% Neem leaves extract, Lambda cyhalothrin 2.5 EC, Imidacloprid 25% WP and Spinosad 240 SC, replicated 3 times. An untreated control plot was left blank as a check plot. Randomize Complete Block Design (RCBD) and Statistix 8.1 was used for analysis. Results show that all the tested treatments were found to be better than the control in reducing the cabbage larvae population. Spinosad 240 SC was found to be the most effective treatment with the lowest larvae population (0.89 and 0.77 larvae leaf-1) and maximum reduction of larvae population (73.04 and 84.01 %) after 1st and 2nd treatment application, respectively. Among botanical extracts, Neem leaf extract was the most effective, with the lowest larval population (1.18 and 1.04 larvae leaf-1) and the highest reduction (57.30% and 75.36%) after the 1st and 2nd treatment applications. The tested treatments were also found to be better than the control in reducing cabbage aphids’ population. Spinosad 240 SC was found the most effective treatment with the lowest aphids population (4.69 and 2.47 aphids leaf-1) and maximum reduction of aphid population (60.97 and 80.31 %) after 1st and 2nd treatment applications, respectively. Compared to other botanical extracts, Neem leaf extract showed the lowest aphid population (6.14 and 3.90 per leaf) with percent mortality of 48.74% and 68.00% after the 1st and 2nd applications. Resulting in the highest yield of cabbage (1005.33 kg ha-1) with cost-benefit ratio (of 5.45) was recorded in Spinosad 240SC, followed by imidacloprid 25%WP (992.33) with cost-benefit ratio (5.79). Among the botanical extracts, Neem leaf extract resulted in a yield of (685 kg/ha) with a cost-benefit ratio of (1.59) was recorded. It was concluded that all the tested insecticides were reducing the population of cabbage larvae and aphids. All the botanical extracts reduce the population of aphids and cabbage larvae, but as compared to other extracts neem extracts showed the best results among them. Hence using Imidacloprid 25% WP, Spinosad 240 SC at District Dadu is recommended for sustainable management of cabbage larvae and aphids.

The study was conducted to evaluate the insecticidal action of two new chemical insecticides and three locally available botanicals. These materials were evaluated for their efficacy against cabbage aphids, Brevicoryne brassicae (L.), under laboratory and field conditions. The laboratory result revealed that Lambda Cyhalothrin (Triger 5 E.CTM) and Emamectin benzoate (Cutter 112 E.CTM) were non-significant difference from the standard check within 1 day after application. The field results showed between the new insecticides, Triger 5 E.CTM and Cutter 112 E.CTM were non-significant difference from that of the standard check (Diazinon 60% E.CTM) at both locations (Guder and Mutulu) within three days after application. Extracts of neem (Azadirachta indica) seed, Hop bush (Dodonae angustifolia) fresh leaf and Lemon grass (Cymbopogon citrates) gave positive performance under laboratory while the efficacy percent were decline at both field locations on field. Azadirachta indica seed, Dodonae angustifolia and Cymbopogon citrates were given 59.48, 57.16 and 52.50 at Mutulu and 53.92, 37.26 and 62.72 at Guder location mortality percent, respectively, after 3rd day observation in first spray. The obtained results revealed that all tested materials were exhibited mortality rate action against cabbage aphids. Powdered neem seed, Dodonae angustifolia fresh leaf and leaves of Cymbopogon citrates caused moderately mortality percent against cabbage aphid within 3 days after applications. Higher damage and low yield were observed in control and botanicals application. This study indicated that the two insecticides Cutter 112 E.CTM and Triger 5 E.CTM and botanicals could be recommended as an alternative management option of Brevicoryne brassicae (L.) in Ethiopia.

Field study was conducted to evaluate the efficacy of biorationals and chemical insecticides against black thrips, Thrips parvispinus (Karny) on chrysanthemum. Thrips population ranged from 15.33 to 13.89/flower before spraying. The efficacy of seven biorationals and seven chemical insecticides were evaluated against black thrips under field conditions. The application of pongamia soap @5g/lit and Spinosad 45% SC @ 0.2 ml/lit reduced the thrips incidence significantly among the biorational and chemical insecticides respectively. The mean per reduction of thrips incidence in pongamia soap @ 5 gm/lit application was 74.90%. This was followed by neem soap @ 5g/lit (72.25%), azadirachtin @10000ppm (71.10%), Beauveria bassiana (66.76%), Isaria fumosorosea (64.93%), Lecanicillium lecanii (63.72%), and Metarhizium anisopilae (62.46%). Among the chemical insecticides Spinosad 45%SC @ 0.2 ml/lt. stood first in the order of efficacy with 80.2% reduction in thrips population. The order of efficacy of chemical insecticides against black thrips in chrysanthemum are spinetoram 11.7%SC (76.245%) > cyantraniliprole 10%OD (73.92%) > fipronil 5% SC (72.24%) > thiamethoxam 25% WG (70.79%) > dinotefuran 20% WG (69.80%) > tolfenpyrad 15% EC (68.02%). The effective biorational and chemical insecticide can be included as a component in the Integrated pest management of thrips complex in chrysanthemum. The rotation of effective compounds will reduce the resistance development against insecticides in thrips associated with chrysanthemum and also reduces the thrips infestation.

Entomopathogenic fungi (EPF) are promising eco-friendly alternatives to chemical insecticides against various insect pests. We assessed the efficacy of different Beauveria bassiana (Bals.-Criv.) Vuill. strains against Brevicoryne brassicae (L.), a major pest of Brassica crops under both laboratory and field conditions. The virulence and endophytic properties of three strains of B. bassiana, the commercial strain GHA, the endemic one KA14 from the Democratic Republic of Congo (DRC), and GxABT-1 from Belgium, were assessed under laboratory conditions. Under field conditions in eastern DRC, the efficacy of the B. bassiana GHA was evaluated compared to that of a conventional insecticide. In vitro, the lethal time 50 (LT50) values ranged from 3days for B. bassiana GxABT-1 to 4days for both GHA and KA14 following direct application of fungi. Aphid exposure to fungus-treated leaves at 7 and 14days after inoculation (DAI) resulted in LT50 values of 4 to 5days for GHA and KA14. Regarding the endophytic potential, B. bassiana KA14 showed higher performance in colonizing plant tissues and improving plant height growth. In the dual-choice tests, aphids were initially attracted to fungus-treated plants at 7 DAI but showed no preference between treated and control plants at 14 DAI. Field trials indicated no significant difference between fungal and chemical insecticide treatments, but both significantly reduced B. brassicae infestation compared to the Control. Our results support the interest of exploring the potential of the endemic B. bassiana KA14 strain against various insect pests and applying different methods.

Cabbage aphid, Brevicoryne brassicae (L.) is one of the major insect pests of brassica crops worldwide. Mainly insecticides are being used for its management which poses hazardous effects on the environment and the applicator. Low efficacy and non-target effect of the available insecticide are the main challenge in the management of the pest in Ethiopia. The use of bio-rational and neonicotinoid pesticides is a promising alternative as they are less vulnerable to resistance development and relatively safe to the environment and the applicator. This study was carried out in 2018/19 cropping season to evaluate the efficacy of plant derived and synthetic insecticides for the management of cabbage aphid and their effect on coccinellid predators on Ethiopian kale. Ten treatments including six synthetic and two botanical insecticides were tested in comparison with the standard check dimethoate 40% EC and the untreated control in Randomized Complete Block Design with three replications. Significant (P<0.05) differences were observed among the treatments in terms of cabbage aphid population reduction and their effect on coccinellid beetles. The botanical mix (Garlic+onion+pepper) and imidacloprid were at par with each other and found to be the best treatment with 93.79% and 91.04% efficacy, respectively. The maximum leaf yield was obtained from imidacloprid (14.18 t/ha) followed by botanical mix (13.45 t/ha) and lufenuron (12.42 t/ha). The highest yield increment over control was obtained from imidacloprid (3.1 t/ha), followed by botanical mix (2.37 t/ha). The botanical mix, imidacloprid and neem seed extract were highly effective in aphid control as well as less hazardous to ladybird beetle (Coccinella septempunctata L.). The highest cost benefit ratio was recorded with profenofos (1:1.14) followed by lufenuron (1:0.2), spinosad and nimbecidine (1:0.18). Results of the current study demonstrated that imidacloprid and plant-based insecticides can reduce aphid populations equally to conventional insecticides and could be used as an alternative component for the integrated pest management (IPM) of cabbage aphid, Brevicoryne brassicae (L.) on kale crop under field condition of smallholder farming system.

The effectiveness of Artemisia absinthium was assessed against the cabbage aphid (Brevicoryne brassicae) and its predator, Coccinella septempunctata in Tambis village, UT of Ladakh. A randomized block design (RBD) was employed to set up the field experiment. To target the cabbage aphids, a 5% concentration was made by powdering the seeds and shoot portions of A. absinthium. Prior to spraying, the infestation level of cabbage aphids was recorded in both the control and treatment plots. The average percentage of aphid infestation before treatment was 76% and 84% in control plot and experimental field, respectively. Following the initial treatment, there was a decline of 9.22% in the aphid population. However, at the end of the seventh week, a notable percentage reduction of 77.91% was recorded. Throughout the course of the first to seventh weeks, the overall percentage reduction consistently increased. Despite a slight decline in the predator population, it was not statistically significant (p > 0.05). The study indicated that A. absinthium extracts in the field proved to be effective against cabbage aphids, while also demonstrating a favorable interaction with natural enemies. These findings highlight the potential of A. absinthium to assist small-scale farmers in protecting their cabbage crops from B. brassicae infestation.

Mango hopper is an important pest of mango that causes severe losses in yield and lower quality of fruit. The objective of the study was to investigate the susceptibility of mango hopper to the selected chemical and botanical insecticides and to find out the efficacy of different concentrations of selected insecticides/botanicals in controlling the mango hopper in the field conditions. Field experiments were conducted at four locations of Punjab, viz. Gurdaspur (Regional Research Station), Hoshiarpur [Government Garden and Fruit Nursery, Khiala Bulanda; FRS, Gangian; Jhandia Kalan (Ropar)] to evaluate different botanicals and chemicals along with Malathion 50 EC as check insecticide during 2019–21. Results indicated that lambda-cyhalothrin 5 ec @1.0 ml/l, imidacloprid 17.8 SL @0.4 ml/l, deltamethrin 2.8 ec @0.5 ml/l, thiamethoxam 25 wg @0.1 g/l, dimethoate 30 ec @1.65 ml/l, buprofezin 25 sc @2.0 ml/l, oxydemeton methyl 25 ec @1.0 ml/l and malathion 50 ec @1.5 ml/l were found significantly effective against mango leaf hoppers with reduction in population from 90–60%. PAU homemade neem extract @14 ml/l and PAU homemade dharek extract @4 ml/l resulted in 28–80% reduction, respectively. These wide options will help the farmers for opting wide range of insecticides and botanicals for need based spraying of these insecticides instead of schedule sprayings.

Aims:Lettuce and broccoli are high value vegetable crops in California. The western flower thrips,Frankliniella occidentalison lettuce, and the cabbage aphid,Brevicoryne brassicaeand the green peach aphid,Myzus persicaeon broccoli are important insect pests that are frequently managed with chemical insecticides.Observation:Efficacy of various chemical insecticides and the entomopathogenic fungusBeauveria bassianawas evaluated against these pests in field studies in the Santa Maria area of California. Some insecticides varied in their efficacy againstF. occidentalisfrom year to year and against different aphid species.Conclusion:A new insecticide sulfoxaflor provided good control of aphids on broccoli.Beauveria bassianademonstrated a potential for broccoli and lettuce integrated pest management.

A field experiments were conducted to determine the comparative efficacy of different chemical insecticides against the fall armyworm, Spodoptera frugiperda (J.E. Smith), in maize under natural field conditions during winter seasons of 2020 and 2021. The experiments were laid out in a randomized complete block design with four replications and seven treatments, namely: chlorantraniliprole 18.5% SC @ 0.4 ml/liter of water; azadirachtin 1500 ppm @ 5 ml/liter of water; spinosad 45% SC @ 0.3 ml/liter of water; spinetoram 11.7% SC @ 0.4 ml/liter of water; novaluron 10% EC @ 2 ml/liter of water; emamectin benzoate 5% SG @ 0.4 g/liter of water; and an untreated control at National Maize Research Program (NMRP), Chitwan, Nepal. The efficacy study revealed that all the treatments significantly reduced plant damage and increased grain yield compared to the untreated control (p < 0.05). Spinosad proved to be the most effective, with a minimum infestation rate of 9.3% followed by chlorantraniliprole (12.4%) and spinetoram (16.5%), compared to the untreated control (79.6%). Spinosad treated plot also yielded the highest grain 4885 kg/ha, followed by spinetoram (4647 kg/ha), chlorantraniliprole (4470 kg/ha) and emamectin benzoate (4335 kg/ha) as compared to the untreated control (1758 kg/ha) in the combined analysis. Although azadirachtin 1500 ppm was the least effective among the treatments, it was still significantly superior to the untreated control. Furthermore, plant height, ear height, cob length, cob diameter, thousand grain weight and grain yield of maize were negatively correlated with foliar damage done by fall armyworm.