Effect of neem on the growth and development of the obliquebanded leafroller, Choristoneura rosaceana

Abstract

Neem, Azadirachta indica A. Juss. (Meliaceae), seed oil (NSO) added to meridic diet at concentrations as low as 0.016% reduced pupation and prevented adult eclosion of obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). At a rate of 0.0016%, NSO reduced the fitness of C. rosaceana, resulting in longer developmental times, lower adult eclosion rates, and reduced egg production compared with controls. The neem insecticide Margosan-O TM produced comparable results based on concentrations of the most biologically active constituent, azadirachtin. Pupation was completely inhibited at concentrations of 0.25% and 1.0% for larvae exposed at 5th or 6th instar, respectively; rates as low as 0.016% reduced pupal weights and adult eclosion rates. For larvae transferred to treated diet at 5th instar, physical abnormalities in the wings of adults occurred at a rate of 0.004% NSO and increased with increasing treatment rates. NSO at concentrations as high as 2.0% was not antifeedant to neonate larvae, based on 24 and 48 h choice test bioassays, when incorporated into a meridic diet.

Effects of neem oil on feeding behaviour and development of the pear sawfly, Caliroa cerasi

“…Mortality increased from 3 to 7 days after treatment, indicating that the larvae were experiencing toxic effects from neem oil for a prolonged period. Similar results have been observed in studies with other insect species such as tortricid leafrollers (Lowery et al, 1996). Increasing doses of neem appeared to extend development times and increase the number of larval moults (Table I).…”

“…As a natural product with short residual action and low mammalian toxicity, it possesses many environmentally-desirable characteristics and may be useful in organic or reduced-pesticide fruit production. Effects of neem oil on the growth and development of lepidopterous pests of tree fruits have been reported (Lowery et al, 1996), However, effects on phytophagous hymenoptera such as the pear sawfly have not been described, so the potential of neem as a control agent for these pests has not yet been determined. The objectives of our experiments were therefore to determine potential antifeedant and growth regulatory effects of neem oil on pear sawfly larvae.…”

Effect of Sweet WormwoodArtemisia annuaCrude Leaf Extracts on Some Biological and Physiological Characteristics of the Lesser Mulberry Pyralid,Glyphodes pyloalis

“…The LC 50 and LC 20 dose of A. annua reduced fecundity and fertility of G. pyloalis. Essential oils of neem Azadirakhta indica similarly reduced fecundity of Choristoneura rosaceana ( Lowery et al 1996 ). In the same way, insects facing the sublethal doses of synthetic insecticides may also show various effects on growth, duration of life stages, pupal weight, and fecundity ( Ansari et al 2000 ; Huang et al 2000 ).…”

Toxicity of insecticides to obliquebanded leafroller, Choristoneura rosaceana, larvae and adults exposed previously to neem seed oil

“…Juss., containing the triterpenoid azadirachtin (AZA) as the most biologically active component (Isman et al, 1990), have elicited a great deal of interest due to their novel modes of action and broad-spectrum of activity toward phytophagous insects (Schmutterer, 1990;Mordue & Blackwell, 1993). Larval Lepidoptera are particularly sensitive to neem and have been the subject of numerous studies, including effects of neem extracts or AZA on growth and development (Simmonds et al, 1990;Lowery et al, 1996), digestion and nutrition (Timmins & Reynolds, 1992), feeding inhibition (Isman, 1993), and physiology (Koul et al, 1987;Barnby & Klocke, 1990).…”