The monitoring of quarantine pest – cowpea weevil Callosobruchus maculatus Fabricius – under storage conditions by using the synthetic sex pheromone

Abstract: One of the most dangerous pests of the genus Callosobruchus spp. is a cowpea weevil Callosobruchus maculatus Fabricius that is widespread in many countries. In Russian Federation the cowpea weevil is a quarantine pest that is mainly imported with foreign freight and could cause serious economic losses. The losses of crop such as cowpeas, mung beans and chickpeas during the storage period can reach 80-100%. At the same time, the germination of beans in the bulk infested by the cowpea weevil is reduced by 50-80%.In 2018 the storage trial was carried out with the aim to study the attractive effect of synthetic sex pheromones on catching insect males of cowpea weevil C. maculatus. The researched work was done in Bulgaria on the base of the Institute of soil, agricultural technology and plant protection named after Nikola Pushkarov. Synthesized in the All-Russian Plant Quarantine Center pheromones were tested with infested beans of the cowpea (Vigna sinensis L.) that were collected in the field. Different pheromone (the blend of five acids: 3-methylene-pentane, (Z)-3-methyl-3-heptene, (E)-3-methyl-3-heptene, (Z)-3-methyl-2-heptene, (E)-3-methyl-2-heptene) dosages (2 mg, 4 mg, 8 mg, 16 mg and 0 mg for control) were applied with two trap types: “delta trap” for wing-bearing insects and “book trap” for flightless forms.Comparison test showed that pheromone dosage of 16 mg and 8 mg applied with “delta” trap had non-significant difference between each other with average number of trapped individuals of 14 and 12, respectively. The trapped quantity of adults was higher in “delta trap” with a dosage of pheromone of 2 and 16 mg and an average of 23 and 14 individuals per trap, respectively. The use of “delta trap” showed a higher attractive effect than the “book trap” with average number of 7 individuals and 68 individuals per trap, respectively. Therefore, in warehouse conditions, the preferred type of trap is “delta”.The obtained results of the biological attractiveness of the pheromones showed its effectiveness by using “delta trap” even in minimum commercial dosage of 2 mg. Evaluation of the pheromone attractiveness is the useful tool for monitoring and could be used in Integrated Pest Management. In addition, in some cases the use of different doses showed the possibility for pest disorientation in storage conditions as well as in the field.