Biological efficacy of CalneemTM oil against the tropical warehouse moth Ephestia cautella (Lepidoptera: Pyralidae) in stored maize

Abstract

The tropical warehouse moth Ephestia cautella (Walker) is an important storage pest of maize grain. The control of this major moth pest relies heavily on the use of synthetic insecticides. We assessed the biological efficacy of a commercial neem oil (Calneem oil) against E. cautella in the laboratory, using the common grain protectant Actellic as a positive control. Contact toxicity, repellency, effects on oviposition, development and grain damage were assessed. The assays were conducted by treating 100 g of maize grains with Calneem oil concentrations of 3, 5 and 7 ml/l; and Actellic at 2 ml/l. Calneem oil significantly (P, 0.05) reduced oviposition rate, development of eggs and immature stages, and emergence rate of E. cautella progeny in maize grains. Grains treated with Calneem oil had significantly (P, 0.05) reduced grain damage in storage, and the oil had a repellency of 53 -70% compared with the negative control. Calneem oil protected maize grain against damage by E. cautella for 10 weeks, compared with 20 weeks protection by Actellic. There was no resistance development to the oil for three generations of E. cautella. The insects that survived treatment with the LC 90 concentration (12.2 ml/l) of the Calneem oil laid fewer eggs, and some of their progeny were deformed. Calneem oil provided a good level of protection to maize grains against infestation by E. cautella, and may therefore be a suitable substitute for Actellic.

Toxic effect of commercial formulations of neem oil, Azadirachta indica A. Juss., in pupae and adults of the sugarcane borer, Diatraea saccharalis F. (Lepidoptera: Crambidae)

“…These results were similar to those of DAD et al (2011), who observed reduced fecundity, limitation in the number of deposited eggs and totally inhibited eclosion after the treatment with neem in Musca domestica larvae. Research, v.194, p.237-244, 1978. Studies with azadirachtin or neem oil on Lepidoptera also demonstrated changes in fertility and fecundity of S. littoralis (PINEDA et al, 2009), anti-oviposition and ovicidal effects against E. cautella (SHEHU et al, 2010), ovicide with changes in the embryonic development against D. saccharalis (SILVA et al, 2013) and extended embryonic period in D. saccharalis (OLIVEIRA et al, 2013).…”

“…Mean ± standard error of longevity, emergency rate, morphological abnormalities and mortality of adults emerged of young pupae and old pupae of D. saccharalis treated with neem oil extract in experimental conditions. rate (KHAN et al, 2007;SHEHU et al, 2010). Artificial diets containing different concentrations of the aqueous extract of A. indica also decreased the survival of D. saccharalis caterpillars (MAZZONETTO et al, 2013).…”

“…Some adults of E. cautella also emerged deformed after treatment of the larvae with Calneem® oil (SHEHU et al, 2010).…”

Toxicity and Residual Activity of a Commercial Formulation of Oil from Neem, Azadirachta indica A. Juss. (Meliaceae), in the Embryonic Development of Diatraea saccharalis F. (Lepidoptera: Crambidae)

“…Their activity is quickly reduced by light; they are only slightly toxic to mammals, and are compatible with the natural foes of several insects [7][8][9]. Studies on the effects on insects treated or fed with azadirachtin have reported growth inhibition; death of caterpillars during ecdysis; prolongation of the larval stage; deformation of caterpillars and adults; decrease in longevity, fecundity and fertility [10][11][12][13]. Azadirachtin in neem oil has selective effects on insects, mostly with respect, impaired feeding and interrupted growth [14,15].…”

“…neem oil directly applied to Lepidoptera eggs, are rare. Some studies have documented the effects on oviposition, following treatment of caterpillar adults or pupae [12,13,17,18]. Ovicide effects of neem solution were reported after application to egg masses of different ages in Diatraea saccharalis F., 1794 (Lepidoptera: Crambidae), but subsequent effects on the development of caterpillars have not been demonstrated [19].…”