The Effect of Some Botanical Pesticides Against Citrus Leafminer (CLM) and Two Spotted Mite (TSM)

Abstract

The novel natural extracts of the higher plants have a variety characteristics including insecticidal, antifungal, antiviral and antibacterial activity, repellence to pests, antifeedant effects, insect growth regulation, toxicity to nematodes, mites, agricultural pests, (Prakash and Rao, 1997). Insecticidal activity of many plants has been demonstrated (Carlini and Grossi-de-Sa, 2002). The deleterious effects of plant extracts on insects can be manifested in several manners including toxicity, mortality, and reduction of reproduction, fecundity and fertility. The plants that used for pest insect control have strongly correlated to medicinal and pesticidal plants (Yang and Tang, 1988). The plant substances contain components that are toxic to insects through a novel mode of action. In addition to the obvious implication of discovering a new target site against which to design insecticides, existing mechanisms of resistance may not confer cross-resistance to these plant extracts. The citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidptera: Gracillariidae), is an important pest of citrus and related rutaceae and ornamental plants almost worldwide (Achor et a., 1996). The CLM mines leaves, surface tissue of young shoots and stems, and less frequently the fruit (Sponagel and Diaz, 1994). Although citrus leafminer causes indirect damage to young leaves, which predisposes them to infection by canker so, controlling citrus leafminer is a vital component of canker management (Pena et al., 1996; Belasque et al, 2005). The first record of CLM from southern and northern Iran, with a dramatic increase and widespread dispersal, was noted in 1961 and 1994, respectively. The pest has about 5-9 generations over year, with peak periods in early summer and early autumn. Preliminary field trials with selected insecticides indicate the superiority of Dimilin (diflubenzuron) over Diazinon, Zolone (Phosalone) and Ekamet (Etrimfos) in controlling CLM in the northern Iran, but it is not totally effective (Jafari, 1996). There is no biological control plan of CLM, but some studies are underway for planned extension activities using biorational insecticides. Several different insecticides, such as Avant, Buprofezin and Pyriproxifen was used (Amiri, 2006 (a)), but these may involve interference in control of the pest by natural enemies (Guerra et al., 1997). However, biological control is the best option for control (Pena, 1997), but the effective control of CLM is very complicated because of its high migration ability from outside of orchards, high fertility, present epidermis of citrus leaf as substantial protection and the difficulty of direct contact of chemical to the larval body. However, CLM