Laboratory assessment of the suitability of predatory bugs Orius laevigatus and Orius majusculus as natural enemies of seed potato pests in greenhouses

Laboratory experiments were performed to test Orius majusculus and Orius laevigatus suitability for potato protection. The adult bugs released on potato plants infested with Myzus persicae can normally survive, mature, and reproduce. In the absence of prey, the bugs can survive for about a week. And though addition of flower pollen increased survival, insect fecundity remained low. Only feeding by Sitotroga cerealella eggs added to potato plants provided for sustainable fecundity of Orius females laying up to 200 eggs during the lifetime. Thus, O. majusculus can be applied for biological control of aphids on seed potatoes in greenhouses and the grain moth eggs can be used as an additional food for the bugs.

Do Development and Diet Determine the Degree of Cannibalism in Insects? To Eat or Not to Eat Conspecifics

Cannibalism in insects plays an important role in ecological relationships. Nonetheless, it has not been studied as extensively as in other arthropods groups (e.g., Arachnida). From a theoretical point of view, cannibalism has an impact on the development of more realistic stage-structure mathematical models. Additionally, it has a practical application for biological pest control, both in mass-rearing and out in the field through inoculative releases. In this paper, the cannibalistic behavior of two species of predatory bugs was studied under laboratory conditions—one of them a generalist predator (strictly carnivorous), Nabis pseudoferus, and the other a true omnivore (zoophytophagous), Nesidiocoris tenuis—and compared with the intraguild predation (IGP) behavior. The results showed that cannibalism in N. pseudoferus was prevalent in all the developmental stages studied, whereas in N. tenuis, cannibalism was rarely observed, and it was restricted mainly to the first three nymphal stages. Cannibalism and intraguild predation had no linear relationship with the different cannibal–prey size ratios, as evaluated by the mortality rates and survival times, although there were variations in cannibalism between stages, especially for N. pseudoferus. The mathematical model’s implications are presented and discussed.

Effects of Vegetation Strips, Fertilizer Levels and Varietal Resistance on the Integrated Management of Arthropod Biodiversity in a Tropical Rice Ecosystem

Integrated biodiversity management aims to conserve the beneficial species components of production ecosystems and reduce the impacts of pests. In 2011 and 2013, experiments were conducted at Los Baños, Laguna, Philippines, to compare arthropod communities in rice plots and on levees with and without vegetation strips. Vegetation strips included spontaneous weeds, sesame and okra (2011), or mung bean (2013). The plots were treated with one of three nitrogen levels and in one experiment were planted with planthopper-resistant (IR62) and susceptible (IR64) rice varieties. Parasitoids and predators of lepidopteran pests and of the ricebug, Leptocorisa oratorius, were more abundant in high-nitrogen rice plots where their prey/hosts also had highest densities. Planthoppers and leafhoppers were more abundant in low-nitrogen plots. Weedy and sesame/okra bunds provided habitat for a range of natural enemies including spiders, parasitoids and predatory bugs, but did not have higher pest numbers than cleared bunds. Higher abundances of the predator Cythorhinus lividipennis and higher parasitism of planthopper (Nilaparvata lugens) eggs by Anagrus sp. were associated with sesame/okra bunds in late season rice plots. Mung bean also provided habitat for key predators and parasitoids that spilled over to adjacent rice; however, mung bean was also associated with higher numbers of lepidopteran and grain-sucking pests in the adjacent rice, albeit without increased damage to the rice. For ricebug in particular, damage was probably reduced by higher parasitoid:pest ratios adjacent to the vegetation strips. Varietal resistance and mung bean strips had an additive effect in reducing abundance of the planthopper Sogatella furcifera and the leafhopper Nephotettix virescens. Reduced numbers of these latter pests close to vegetation strips were often compensated for by other plant-sucking bugs, thereby increasing the intensity of potentially stabilizing interspecific interactions such as competition. We highlight the benefits of diversifying rice landscapes and the need to optimize vegetation strips, e.g., by including lepidopteran trap-plants, for intensive rice production systems.

Description of a Bizarre New Genus and Species of Ambush Bugs from the Dominican Republic (Heteroptera: Reduviidae: Phymatinae)

Enigmatic and rarely collected, ambush bugs of the tribe Macrocephalini (Heteroptera: Reduviidae: Phymatinae) encompass a diverse group of predatory bugs armed with subchelate raptorial forelegs, a greatly enlarged scutellum, and elongate head. Macrocephalini is the most specious of the four tribes of ambush bugs, consisting of 20 genera and 154 species. They are represented in the Caribbean by several remarkable taxa that bear foretarsi, a trait unassociated with macrocephalines found elsewhere in the world. I here describe a new genus and species of Macrocephalini, Capricephala chiaroscuro gen. et sp. nov., native to the island of Hispaniola and one that bears striking differences to other phymatines known from that region.

The evaluation of potato virus Y transfer by some beneficial bugs (Hemiptera: Heteroptera)

Pazyuk IM, Fominykh TS. 2019. The evaluation of potato virus Y transfer by some beneficial bugs (Hemiptera: Heteroptera). Biodiversitas 20: 1222-1227. The predatory bugs Podisus maculiventris, Orius majusculus, Nesidiocoris tenuis, and Macrolophus pygmaeus were commonly used for control of pests in potato meristem culture in greenhouses. In this study, the risk of transmission of potato virus Y (PVY) by entomophagous bugs was estimated in cage experiments. It has been shown that none of the bugs tested was capable of transmitting the PVY. However, N. tenuis and M. pygmaeus have been shown to damage potato seedlings in the absence of animal food (pests or factitious food). The bug N. tenuis caused severer damage to potato plants than did the bug M. pygmaeus. Therefore, we can recommend only P. maculiventris and O. majusculus for pest control in potato meristem culture in greenhouses.