Acaricidal effects of methyl benzoate against Tetranychus urticae Koch (Acari: Tetranychidae) on common crop plants

Abstract

BACKGROUND: Methyl benzoate (MB) is a small, hydrophobic organic compound isolated from the freshwater fern Salvinia molesta (Salviniales: Salviniaceae). It is used as a fragrance and flavor enhancer owing to its pleasant smell. It has also demonstrated potential as a green pesticide for various groups of insects. However, its effects on mites are yet to be studied.RESULTS: Here, we assessed the acaricidal and repellent effects of MB against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), under laboratory and greenhouse conditions. MB demonstrated concentration-dependent contact toxicity against eggs and adults of the mite. A leaf-dipping assay using 1% MB prevented the hatching of 92.7% of eggs and killed 100% of adults within 48 h of treatment. Concentration-mortality statistics were subjected to probit analysis, and the median lethal concentration (LC 50 ) values for eggs and adults were 0.25% and 0.5%, respectively. Treatment with 1% MB showed the highest mortality (100%), with a median lethal time (LT 50 ) estimated of 8.1 h. The efficacy of MB against adults of T. urticae on tomato plants under greenhouse conditions was 97.5% within 96 h post-treatment. Further, MB showed significant repellent activity against adult females of T. urticae, although this declined with time. Spraying with 1% MB (three times per plant) was not phytotoxic to bean, cucumber, pepper, or tomato plants.CONCLUSION: MB is highly acaricidal and repellent, but not phytotoxic, and is a promising green pesticide.

Effects of Sublethal Doses of Methyl Benzoate on the Life History Traits and Acetylcholinesterase (AChE) Activity of Aphis gossypii

“…Our recently published results show that MB was acutely toxic to several arthropods, namely Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), Tetranychus urticae Koch (Acari: Tetranychidae), and A. gossypii. However, MB was much less toxic to the non-target organisms, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) and Nesidiocoris tenuis Reuter (Hemiptera: Miridae) [21][22][23][24]. Based on the above results, MB has potential as a safe, or "green", pesticide that can be applied in integrated pest management.…”

“…Natural products can often provide a more environmentally-friendly approach to managing insect pests and plant diseases [42,43]. MB, which is a naturally occurring compound found in many plants, exhibits potent insecticidal activity against a variety of insect pests [18,[21][22][23][24]44]. Therefore, MB could provide an alternative to synthetic insecticides for agricultural control of cotton aphids in the near future.…”

Lethal and Sublethal Effects of Methyl Benzoate on the Predatory Bug Nesidiocoris tenuis

“…MB is highly effective at 1% concentration when used against whitefly, aphid and mite pests: it can cause >70% mortality of these arthropods under laboratory and greenhouse conditions [ 30 , 31 , 32 ]. In contrast, our present results indicate that 1% MB does not cause high mortality or adverse feeding effects on N. tenuis .…”

“…MB solutions (0.25%, 0.5% and 1%) were prepared according to the developed method published by Mostafiz et al [ 30 ]. These MB concentrations were tested on N. tenuis because they are known to be suitable for pest control of whiteflies, aphids and mites [ 30 , 31 , 32 ]. Distilled water containing 0.5% Tween 20 ( v/v ) and 0.5% Tween 80 ( v/v ) was used as a negative control.…”

“…Benzyl methyl ester, also known as methyl benzoate (MB), is a volatile organic compound (often derived from fermented apple juice) found in many plant species [ 28 ]. MB has recently been shown to have acute toxic effects on various insect species including whiteflies, aphids and mites [ 29 , 30 , 31 , 32 ], which are the prey of N. tenuis . Possible non-target effects of MB on natural enemies have yet to be fully investigated.…”