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The aim of the study was to examine the possibility of applying methyl jasmonate (JA-Me) and acibenzolar-S-methyl (BTH) to reduce the population of mites in apple orchards. The experiment was performed on apple trees cv. “Golden Delicious” grown in an orchard according to Integrated Pest Management (IPM) principles. The study showed that of the two elicitors, JA-Me restricted the population of the European red mite (Panonychus ulmiKoch) more strongly than BTH. Neither of these compounds significantly affected the size of the population ofTyphlodromus pyriScheuten – a beneficial predatory mite feeding on spider mites in apple orchards. The study also showed no adverse effects of these compounds on the yield and growth of apple trees, nor on their reproduction as measured by seed production. Studies indicate that the use of methyl jasmonate against spider mites on apple trees can complement the use of conventional acaricides as well as the introduction of predatory mites of the family Phytoseiidae in the protection of apple orchards. [ABSTRACT FROM AUTHOR]

Ethanol extracts obtained from the leaf of the thorn apple (Datura stramoniumL.) (Solanaceae) were examined for lethal and repellent properties against adults of the European red mitePanonychus ulmi(Koch) (Acari: Tetranychidae) and its predatorStethorus gilvifrons(Muls.) (Col.: Coccinellidae) under laboratory conditions. The Petri leaf disc-spray tower method was used. The results showed thatD. stramoniumleaf extracts were lethal to both the mite and its predator. Furthermore, an increase in the dose of leaf extract caused a significant increase in the death rates of bothP. ulmiandS. gilvifronsadults. Probit analysis and parameter estimation showed that the LC50values of leaf extract were 7097.5 and 1853.9 mg/l at 24 h residual activity for spider mite and ladybird adults, respectively. The mite and ladybird mortality rates associated with the extract were higher at 48 h than at 24 h, with LC50values of 2013 and 1030 mg/l, respectively. However, the LC90values of the extract were lower for ladybirds than for spider mites at both 24 and 48 h. According to Pearson’s chi-squared test, both spider mite and ladybird adults showed strong aversions to apple leaf surfaces sprayed with sub-lethal doses of the extract (from 13.72 to 1058.0 mg/l). Moreover, an odour test using a two-choice olfactometer demonstrated that ladybird adults prefer fresh air to the extract odour. These results suggest thatD. stramoniumextract can be used effectively as a safer phytopesticidal product for the management ofP. ulmiin both organic and inorganic apple production, but it is not suitable for use in integrated pest management strategies due to its toxic and repellent effects againstS. gilvifrons. [ABSTRACT FROM PUBLISHER]

The ladybird beetle Stethorus gilvifrons (Muls.) does not provide sufficient mite control in many of the apple orchards in Bursa, despite being an effective and voracious predator of the European red mite, Panonychus ulmi (Koch). This is due in large part to a heavy dependency on organophosphate (OP) and synthetic pyrethroid (SP) insecticides, which were applied to target key pests. To help understand the effects of the insecticides on the ladybird beetle and its main prey, P. ulmi, this study aims to determine their susceptibilities to the residues of parathion-methyl and bifenthrin and detoxifying enzyme activities, such as carboxylesterase (CarE) and glutathione S-transferase (GST). In addition, the insensitivity of acetylcholineesterase (AChE) to the inhibitors, paraoxon and primicarb, is also determined. There are differences in susceptibility to parathion-methyl, in CarE activity and AChE insensitivity, among the populations of predator ladybird and the spider mite. Although GST might play an important role in detoxifying OPs, there is no relationship between susceptibility to parathion-methyl and bifenthrin and GST activity in both the ladybird and the spider mite. On the other hand, two S. gilvifrons populations were surprisingly tolerant to two insecticides. The disparity in susceptibility to parathion-methyl among the predator populations was due to the responsibility of multiple biochemical resistance mechanisms, including elevated CarE activity and target-site insensitivity. Furthermore, the tolerance of the two populations of ladybirds to bifenthrin was similar to that of two P. ulmi populations collected from the same orchards, which indicates a coadaptation to SPs. Therefore, enhanced detoxification by increased activity of CarE is largely responsible for the observed tolerance to bifenthrin in S. gilvifrons populations. Consequently, these results demonstrate that the ladybird species tend to develop resistance to insecticides in the field. [ABSTRACT FROM AUTHOR]