Natalia A. Belyakova

Wolbachia screening in mites is necessary for understanding of how their biological functions can be affected, including development of approaches to induce parthenogenesis, making the predator’s cultures more effective and stable. Here we studied Wolbachia infection in two sibling species of Neoseiulus predatory mites (one thelytokous and another bisexual) as well as their feed mites to test two working hypotheses: 1) a thelytokous mite Neoseiulus agrestis harbors Wolbachia, unlike its bisexual sibling species Neoseiulus neoagrestis and 2) feed mites are not the source of Wolbachia detection in Neoseiulus. To test these hypotheses, we performed PCR screening and multilocus sequence typing. It showed Wolbachia infection in N. agrestis, but not N. neoagrestis. Since the former is a thelytokous species, and the latter is not, Wolbachia might contribute to this peculiarity. The Wolbachia isolate from N. agrestis belongs to the supergroup B, being similar to the strains from lepidopteran insects as well as Syrphidae (Diptera). Wolbachia infection status of the thelytokous species N. agrestis is shown for the first time. As for the feed mites, Wolbachia was not detected in Carpoglyphus lactis and Thyreophagus entomophagus, but occurred in Tyrophagus putrescentiae. That bacterial strain formed a basal branch in relation to the supergroup B and demonstrated only a partial genetic identity to the Czech isolate from T. putrescentiae. Thus, Wolbachia from the predatory and feed mites are genetically different. The new Wolbachia sequences are deposited to GenBank serving as an important source of molecular data for comparative studies of Wolbachia parasites.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a super pest that seriously endangers the development of the agricultural economy worldwide. To prevent and control B. tabaci, insecticides have been used for many years, which has inevitably led to increased tolerance to chemical agents. To elucidate the development of field resistance and more scientifically and efficiently control B. tabaci, in December 2024, we conducted bioassays on B. tabaci on soybeans in Suzhou, Anhui Province, using 14 insecticides. These fourteen insecticides, namely, abamectin, spinetoram, thiamethoxam, flupyradifurone, imidacloprid, dinotefuran, acetamiprid, thiacloprid, nitenpyram, bifenthrin, deltamethrin, pyridaben, flonicamid, and emamectin benzoate, have multiple action sites and have all shown good control effects on B. tabaci. The results revealed that B. tabaci has developed high resistance to many insecticides and that some insecticides have even tended to fail, but B. tabaci is still sensitive to a small number of insecticides. Different biotypes of B. tabaci differ significantly in terms of insecticide resistance. We determined that the population of B. tabaci on soybean in Suzhou was the MED (Q) biotype. It carried the TYLCV virus, with a virus carrying rate of 60%, but did not carry ToCV or CCYV.

Preference for, and suitability of three plant species: Kalanchoe blossfeldiana, K. daigremontiana, and K. laciniata for oviposition by females of a predatory bug Orius laevigatus were investigated under laboratory conditions. The study was aimed at the improvement of the methods for laboratory and mass rearing of this entomophage widely used for biological control of greenhouse pests. The evaluated parameters were the number of eggs laid per leaf by O. laevigatus females within 24 h and the proportion of hatched larvae. The experiments showed that all three Kalanchoe species are more or less equally suitable as substrates for egg-laying by O. laevigatus females, although when possible it is preferable to use K. blossfeldiana.

Feeding on mixed, alternating, or changing diets often favor insect development. With the aim to optimize mass rearing and use for the biological control of insect pests, we investigated the effects of various combinations of high-quality (the green peach aphid Myzus persicae) and low-quality (eggs of the grain moth Sitotroga cerealella) foods on the larval development of a predatory ladybird Cheilomenes propinqua. In the first experiment, eggs and aphids were mixed in different proportions; in the second experiment, larvae switched from feeding on aphids to feeding on eggs. Although the beneficial additive effect of mixed foods was detected in some treatments with limited diets, feeding on various combinations of eggs with aphids never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids. For the practice of biological control, we conclude that, if necessary (for example, in the case of temporary shortage or a lack of aphids in mass rearing facilities or in the case of preventing release of C. propinqua adults in greenhouses), C. propinqua larvae can be fed with grain moth eggs by replacing, mixing, or alternating with aphids, although this will inevitably result in a proportional decrease in pre-adult survival, rate of development, weight, and size of the emerging adults. On the other hand, even a minimal addition of aphids can have a substantial positive effect on larvae fed with grain moth eggs.

New trends in the technologies of mass breeding of entomophages and their use for biological pest control in greenhouses have been analyzed. The widespread use of new crop varieties, the spreading of new cultivation techniques in the Russian greenhouse crop production, and the increasing number of invasive pests make the selection criteria for entomophages more complicated and increase the need for adaptability of predators and parasitoids. The genetic selection methods of improving entomophages become more important in this context, including the methods for obtaining lines resistant to various phytosanitary preparations. The review covers the current range of entomophages and the directions of their further screening. A gap is noted between the current efforts in studying the ecology of entomophages and the information that is urgently needed for effective screening of species and their further adaptation in modern industrial greenhouses.

Laboratory experiments revealed individual variability in the intensity of day and night movement activity of starved and fed adults of a predatory ladybird Cheilomenes propinqua . Statistical analysis of the experimental data showed that (1) individual variability of day and night movement activity is determined by di erent parameters of Ch. propinqua adults, (2) environmental factors also have di erent impacts on the rate of individual variability of day and night movement activity, and (3) e ects of temperature and starvation on modi cations of day and night movement activity are also di erent. These results suggest that day and night movement activities of Ch. propinqua adults are determined by di erent physiological mechanisms.

It is known that food has a double impact on females of predatory ladybirds: qualitative signal effect (the onset of oogenesis) and quantitative nutritional effect (the increase in oogenesis intensity). We compared the patterns of these effects by feeding Cheilomenes propinqua females on mixed diets: unlimited low-quality prey (eggs of the grain moth Sitotroga cerealella) and limited high-quality prey (the green peach aphid Myzus persicae: 0, 2, 10, and 50 aphids per day). About half of the females fed only on the grain moth eggs oviposited and their fecundity was very low. Daily consumption of 2 aphids increased the proportion of egg-laying females whereas only consumption of 10 aphids increased their mean fecundity. Thus, the threshold of the signal effect was lower than that of the nutritional effect. As applied to mass rearing, we conclude that the addition of high-quality prey to low-quality food causes a substantial increase in egg production, although the economic feasibility of this method is not clear. Regarding biological control of pests by preventing colonization, we conclude that the fecundity of C. propinqua females supplied with the grain moth eggs in the absence of aphids will be low but the appearance of pests will cause a proportional increase in the mean fecundity of ladybirds.

The peculiarities of agriculture technologies in modern greenhouse cause complications in screening of natural enemies, because of increasing the requirements for their adaptive abilities, feasibility of cost-effective mass production, long-term storage and transportation. To be effective in greenhouses species should start breeding as quickly as possible as pest hot spots have appeared. Adopted for greenhouses natural enemies have mainly ruderal life strategy. Regular invasions of new phytophages have an impact on plant protection systems. At the same time, the programs for the introduction of new natural enemies have been stopped due to the potential negative impact of the introduced species on the biodiversity of indigenes species communities. The review analyses the changes in screening of natural enemies that occurred as a result of the introduction of new crop production technologies and the complication of the phytosanitary situation.

The ability of the females of the predatory ladybird Cheilomenes propinqua to survive and to retain reproductive potential in the absence of natural food (aphids) was estimated under various hydrothermal (temperatures of 7, 12, 17, 22, and 27 °C; air humidities of 50% and 80–90%) and trophic (starved vs. fed on the frozen eggs of the grain moth Sitotroga cerealella) conditions. The post-storage reproductive potential was estimated using the mean number of eggs laid over 20 days. The experiments showed that fed females can be stored at temperatures of 15–17 °C for 20 days with a rather low (about 20%) and for up to 80 days with an acceptable (not more than 50%) loss of the reproductive potential. The successful short-term (up to 3 days) storage or transportation of fed and starved females can occur at temperatures from 12 to 27 °C. However, storage for more than 10 days at temperatures of 7 °C and lower results in the 100% mortality of both the starved and fed beetles. These data suggest that (1) in greenhouses, C. propinqua can be used for the biological control of aphids by preventing colonization, although this would require the regular supplementation of factitious food, and (2) escaped individuals would not survive the winter even in the south of the temperate zone.

Проведен анализ новых тенденций в развитии технологий массового разведения и применения энтомофагов для биологического контроля вредителей в защищенном грунте. Широкое использование новых сортов сельскохозяйственных культур, повсеместный переход отечественного тепличного растениеводства на новые технологии возделывания, рост числа вредителей-инвайдеров - все это приводит к усложнению критериев отбора энтомофагов и повышению требований к адаптационным способностям хищников и паразитоидов. В данной ситуации усиливается роль селекционно-генетических методов улучшения энтомофагов, в том числе для получения линий, резистентных к препаратам разного фитосанитарного назначения. В обзоре приведены сведения о современном ассортименте энтомофагов и направлениях их дальнейшего скрининга. Отмечен имеющийся разрыв между текущими научными усилиями в изучении экологии энтомофагов и теми знаниями, которые насущно необходимы для эффективного скрининга видов и дальнейшей их адаптации в современных индустриальных...