Side Effects Of Copper Fungicides On Amblyseius Cucumeris By Laboratory Bioassays

Bulletin of Insectology 64 (1): 69-72, 2011 ISSN 1721-8861

Side effects of copper fungicides on Amblyseius cucumeris by laboratory bioassays
Runqian MAO1,2, Jihuan ZHENG2, Runjie ZHANG1 1 Institute of Entomology / State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P. R. China 2 Guangdong Entomological Institute, Guangzhou, P.R. China

AbstractThe predatory mite, Amblyseius cucumeris (Oudemans) (Acari Phytoseiidae), is an important biological control agent of thrips and pest mites in many various crops. To understand the side effect of copper fungicides on A. cucumeris, the toxicity of three copper fungicides, namely 77% copper hydroxide WP, 30% DT (copper succinate + copper glutarate+ copper adipate) WP and 95% copper gluconate, on thepredatory mite were determined using “Slide-dip immersion method” in the laboratory. The results showed that the LC50 of 77% copper hydroxide WP, 30% DT WP, and 95% copper gluconate to A. cucumeris was 16.5032 × 103 mg/l, 19.6118 × 103 mg/l, and 92.3287 × 103 mg/l, respectively; based on the toxicity rating and the recommended field concentration, it was suggested that the three copperformulations had low or moderate toxicity to A. cucumeris. Key words: copper fungicide, copper gluconate, toxicity, Amblyseius cucumeris.

Introduction The predatory mite, Amblyseius cucumeris (Oudemans) (Acari Phytoseiidae), is an important biological control agent of various species of insect pests and mites, such as the western flower thrips, Frankliniella occidentalis (Pergande), in greenhousevegetables and ornamentals (Gillespie, 1989; Larsen et al., 1998; Williams, 2001; van Houten et al., 2005). The A. cucumeris has becomes one of the most widely used bio-control agents due to the success of large-scale commercial production. In China, It is also called a “biological pesticide” (Zhang et al., 2002). Moreover, the field studies suggested that A. cucumeris is a desirable bio-control agent tocontrol the important citrus pest mites, Panonychus citri (McGegor) (Acari Tetranychidae) and Phyllocoptruta oleivora (Ashmead) (Acari Eriophyidae) (Zhang et al., 2003; 2004). Copper compounds have been widely used in citrus pest management (McCoy et al., 2010), especially for control of citrus fungal diseases (Albrigo et al., 2005), like melanose, greasy spot and canker etc. (Schutte et al.,1997). For example, copper-based fungicides are a standard control measure worldwide for controlling citrus canker (Leite and Mohan, 1990; Das, 2003). Citrus is an important economic fruit crop in southern China. Numerous species of insects, mites and disease pathogens are being threatened its production. Copper hydroxide, a common inorganic copper fungicide, was found to be very effective incontrolling the disease. Organic copper fungicides, such as DT, Copper ammonium (Chen, 1998), cupric acetate (copper acetate) (Chen, 2008), copper abietate etc were also used to control the citrus canker. Integrated pest management programs (IPM) require pesticides to be effective against target species and at the same time to be relatively harmless to non-target parasitic and predatory arthropods (Lee etal., 2002). Eva-

luation of the effects of pesticides on natural enemies and other non-target organisms is an essential requirement in IPM programs (Kavousi and Talebi, 2003). Most fungicides often have very subtle toxic effects on predacious mites and they must be thoroughly evaluated before they are implemented in IPM programs (Bostanian et al., 2009). Compared with conventional insecticidesand acaricides, copper fungicides were considered to be more compatible with the natural enemies of pests (e.g. Metcalf, 1980). However, various species of predatory mites responded differently to a certain copper formulation. Copper hydroxides is the harmless to some predatory mites (Bernard et al., 2004), but its adverse impacts were found on the predatory mite, Agistemus industani Gonzalez...