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The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one of the major insect pests which renders the fruit to become unfit for human consumption. In severe cases, losses may reach up to 100% in some fruit crops. The present study aimed to investigate the pathogenicity of entomopathogenic nematodes (EPNs), Heterorhabditis bacteriophora, H. indica, Steinernema carpocapsae, and S. asiaticum against B. dorsalis maggots and pupae under laboratory conditions. One milliliter of EPNs, having 50, 75, and 100 infective juveniles (IJs) against maggots and 100, 150, and 200 IJs against pupae, were poured into 9 cm Petri dishes with 20 g sterilized soil as supporting media. The highest maggots' mortality (70%) was obtained after 3 days of application of H. bacteriophora and S. carpocapsae and reached up to (96%) after 9 days. S. asiaticum and H. indica caused 91.16 and 85.87% mortality, respectively, after 9 days post treatment at the highest nematode concentration (100 IJs/ml). Whereas, against the fruit fly pupae, H. bacteriophora caused 69.08% mortality after 9 days at the highest concentration (200 IJs/ml). All nematode species showed high effectiveness against both stages of B. dorsalis. Their application can be further evaluated under field conditions to promote a good biological control of fruit flies for healthier fruit production.

Background Numerous biotic and abiotic factors are responsible for losses of grains quality and quantity during storage. Insecticides used to control stored grain insect pests are not only hazardous to mammals and environment but also induce resistance in insect pests towards these synthetic chemicals. A current trial was conducted, during 2020, in a stored grain laboratory at the College of Agriculture, BZU, Bahadur Sub Campus, Layyah, Punjab, Pakistan. A diatomaceous earth (DE) formulation enhanced with bitterbarkomycin (DEBBM) and combined with Beauveria bassiana (Balsamo) Vuillemin was evaluated against Cryptolestes ferrugineus, (Stephens) (Coleoptera: Laemophloeidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Coleoptera: Tenebrionidae) under laboratory conditions. Results DEBBM was applied at the rate of 50 mg/kg, DE (150 mg/kg) and Beauveria bassiana (1.5 × 108 and 1.5 × 1010 conidia/kg) alone as well as in combination with wheat, rice and maize. Treated adult mortality was recorded at 7, 14 and 21 days after exposure. Results of the current study showed that insect pest mortality was maximum in the case of combined application of DEBBM with B. bassiana (high concentration) at prolonged exposure time as compared to their alone application. Mortality of C. ferrugineus was maximum in wheat and rice (100%) over maize (97%), while, R. dominica exhibited high mortality in wheat (100%) followed by rice (97%) and maize (94%) at combined application of DEBBM with B. bassiana (high concentration) after 21 days. Regarding T. castaneum mortality was high in wheat (100%) followed by rice (93%) and maize (88%) in case of combined application of DEBBM with B. bassiana (high concentration) at prolonged exposure time (21 days). Conclusion In crux, the current trial showed that a mixture of DEBBM and B. bassiana is helpful in controlling tested insect pests.

To cite this paper: Aatif, H.M., N. Javed, S.A. Khan, S. Ahmed and M. Raheel, 2015

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