Survival Analysis of the Green Lacewing, <i>Chrysoperla externa</i> (Hagen) Exposed to Neem-Based Products

Abstract

Brazil is the country which has produced the most coffee for over 150 years, and to achieve high productivity, pesticides are the most common control measure for pests. Due to the need to adopt less impactful control practices, natural enemies or insecticides of botanical origin have been studied as alternatives to synthetic insecticides. However, botanical pesticides can negatively affect some natural enemies, and the effect depends on the formulation and concentration. The objective of this study was to estimate the survival of green lacewing larvae, Chrysoperla externa (Hagen), exposed to different doses of neem-based products, whose active ingredient is azadirachtin (Azamax®: 0 (control treatment with distilled water), 12, 24, 36, 48, 60, 72, 84, 96, and 108 mg a.i. L−1; Organic neem®: 0, 3.3, 6.6, 9.9, 13.2, 16.5, 19.8, 23.1, and 26.4 mg a.i. L−1; Natuneem®: 0, 3.8, 7.5, 10.5, 15.0, 18.8, 22.5, 26.3, 30.0, and 33.8 mg a.i. L−1), using a parametric approach. Predator larvae were exposed to neem-based insecticides and evaluated for 20 days. Survival curves estimated by the models—Log-logistic for Azamax®, Weibull for Organic neem®, and Log-normal for Natuneem®—demonstrated an inverse relationship between increasing doses and survival time. These concluded that the application dose should be less than 84 mg a.i. L−1 for Azamax®, 19.8 mg a.i. L−1 for Organic neem®, and 26.3 mg a.i. L−1 for Natuneem® to keep 50% of the green lacewings alive for 13 days, which is the average time for the larval cycle of C. externa.

Keywords

• azadirachtin
• biological control
• biopesticides
• failure-time analysis
• survival models