eChapter Name: Insect Resurgence against Insecticides
9789358876963
eBook Name: A GUIDE TO INSECTICIDE TOXICOLOGY
by Srinivasa Reddy, Rajesh Chowdhary L., Thammali Hemadri
Farmers still rely heavily on insecticides because of their efficiency, portability, and speedy returns on investment. Although synthetic organic insecticides are highly efficient, their widespread usage has led to toxicity to natural enemies, toxic residues in plants and the environment, insect resistance, and a resurgence in insect populations. Ripper (1956) first time recognized the problem of resurgence in plant protection.
Metcalf (1986) distinguished between two types of resurgence: primary insect resurgence, in which populations of target insects that had been suppressed by insecticide application quickly recover to excessive levels (Fig. 1.A), and secondary insect outbreak, in which non-target species develop into serious insect s after insecticide application (Fig. 1.B).
Primary insect resurgence
Primary insect resurgence occurs when the target insect population increases to at least as high (Hajek, 2004) or higher (Hardin et al., 1995) than in an untreated control or higher than before the treatment (Pedigo and Rice, 2006).
Secondary insect resurgence/ secondary insect outbreak (Type II resurgence)
The phenomenon known as replacement of a primary insect with a secondary insect, or secondary insect outbreak, occurs when the population of a non-target insect, which is harmful to the crop, experiences a surge following the application of a insecticide aimed at controlling the population of the primary insect. A second insect outbreak is also called resurgence. A secondary insect outbreak is the rise of a non-target species after an insecticide has been used.