9.4.4 Chemical Control

Insecticides are the primary tool used to control T. absoluta (Bielza, 2010), which has led to many insecticide resistant populations. For example, resistance to cartap, abamectin, and permethrin in Brazil (Siqueira et al., 2000, 2001), and to pyrethroids in Chile (Salazar and Araya, 1997) and Argentina (Lietti et al., 2005) have been reported. Yet, insecticide use for T. absoluta management remains high. There are clear differences in efficacy among commercial insecticides on populations of T. absoluta (Braham and Hajji, 2012; Hanafy and El-Sayed, 2013). Among three bioinsecticides (spinetoram, spinosad, and emamectin) evaluated in tomato fields in Egypt, spinetoram was the most effective and Emamectin was the least (by about twofold) effective (Hanafy and El-Sayed, 2013). In that same study, spinetoram resulted in greater efficacy than the standard insecticides Pyridalyl and Indoxcarb. In numerous field trials in Tunisia among a suite of

biorational insecticides (including spinosad, kaolin clay, and plant extracts such as neem) and synthetic insecticides, efficacy was high (around 90% mortality) for spinosad and emamectin benzoate, but was low for triflumuron, diafenthiuron, and the plant extract Tutafort (Hanafy and El-Sayed, 2013). Treatment of tomato for T. absoluta control with either azadirachtin or chlorantraniliprole resulted in no adverse impact on adult survival or egg hatch of predatory bugs (Amphiareus constrictus (Stål) and Blaptostethus pallescens Poppius). However, nymphal survival of the predators was reduced (Gontijo et al., 2015). As novel insecticides become available, it is important that they are used judiciously, combining them with all other available tools for T. absoluta management and rotating modes of action to hinder the development of insecticide resistance.