Mechanisms of dispersal and colonisation in a wind-borne cereal pest, the haplodiploid wheat curl mite

Dispersal and colonisation determine the survival and success of organisms, and influence the structure and dynamics of communities and ecosystems in space and time. Both affect the gene flow between populations, ensuring sufficient level of genetic variation and improving adaptation abilities. In haplodiploids, such as Aceria tosichella (wheat curl mite, WCM), a population may be founded even by a single unfertilised female, so there is a risk of heterozygosity loss (i.e. founder effect). It may lead to adverse outcomes, such as inbreeding depression. Yet, the strength of the founder effect partly depends on the genetic variation of the parental population. WCM is an economically important pest with a great invasive potential, but its dispersal and colonisation mechanisms were poorly studied before. Therefore, here we assessed WCM dispersal and colonisation potential in relation to the genetic variation of the parental population. We checked whether this potential may be linked to specific pre-dispersal actions (e.g. mating before dispersal and collective behaviour). Our study confirms that dispersal strategies of WCM are not dependent on heterozygosity in the parental population, and the efficient dispersal of this species depends on collective movement of fertilised females.

Vine Weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae), Management: Current State and Future Perspectives

Vine weevil, also known as black vine weevil, Otiorhynchus sulcatus, has been one of the most economically important pest species of global horticultural crops for the past five decades. This period has seen many changes in crop protection practices, including wide-scale adoption of biological controls such as entomopathogenic nematodes and fungi in place of conventional synthetic insecticides. Despite the experimental efficacy of these controls, growers continue to report significant crop losses associated with vine weevil infestation. We argue that simply switching from synthetic insecticides to biological controls, rather than using these controls as part of an integrated management program, is a key factor in the continued importance of this pest. An improved understanding of vine weevil biology and ecology is at the center of the development of truly integrated pest management programs. To this end, we identify opportunities created through recent vine weevil research and highlight key knowledge gaps in which further research may contribute to improved future management approaches.

Effect of Larval Density of Helicoverpa armigera (Hubner) on Pod Damage and Yield of Chickpea

Background: Chickpea (Cicer arietinum L.) is cultivated in almost all parts of world covering more than 50 countries spread over Asia, Africa Europe, Australia, north America and South America countries and is the second most important food legumes crop after common bean (Phaseolus vulgaris L.). Chickpea has played a major role in realization of pulse Revolution in india making the country near self-sufficient in pluses. Gram is extensively grow in india. Due to its high nutritional value and its ability to fix atmospheric nitrogen, its more widely cultivated rabi pulse crop. The gram pod borer Helicoverpa armigera (Hubner) is most important pest of chickpea. Many pesticides were so far tested against this pest but due to over use of these pesticides resistance, residue and resurgence problems arises, beside destruction of natural enemies. Methods: To determination of per cent pod damage and yield of chickpea due to different larval density of H. armigera is an important tool to reduce the cost of cultivation by avoiding the unnecessary use of pesticides. Therefore, a pot experiment was conducted in arranged in a completed randomized design with four replications. The pots were placed under natural field conditions and take observation at Research farm, Rajasthan Agricultural Research Institute, Durgapura, Jaipur during 2015-16 and 2016-17. Result: The results revealed that least per cent pod damage (29.05, 24.78%) was recorded when the larval population was one per plant, while the maximum pod damage (64.55 and 67.76%) was recorded during 2015-16 and 2016-17, respectively. The simple liner correlation analysis indicated that there was a significant positive correlation (r= 0.989 and 0.999) between the larval density and per cent pod damage. Further, a significant correlation was noticed between larval density and number of healthy pods per plant, reduction in yield, yield per plant, total number of pod and damaged pods were -0.964, -0.976; 0.98, 0.986; -0.98, -0.986; 0.117, 0.126 and; 0.985 and 0.992, respectively during 2015-16 and 2016-17.

The Handsome Cross Grasshopper Oedaleus decorus (Germar, 1825) (Orthoptera: Acrididae) as a Neglected Pest in the South-Eastern Part of West Siberian Plain

Oedaleus decorus is a widely distributed acridid over the Eurasian semi-arid territories, from the Atlantic coast to the Pacific coast. In many semi-arid territories, O. decorus was and is the most important pest, but in the south-eastern part of West Siberian Plain, it was not considered a pest until the 1960s. We compared two sets of data on the acridid distribution in the region: before 1960 and from 1961 until 2021. Until the 1960s, the species occurred mainly in the southern steppes. Since the 1960s, its distribution changed significantly. Nowadays, it occupies almost all local steppes and the southern part of the forest-steppes and can be also found on the eastern side of the Ob River. These shifts may be explained by both climatic changes and changes in human activities. During upsurges the densities of O. decorus were often more than one to two adults per square meter. It is often abundant in the same habitats and in the same periods as the Italian locust (Calliptamus italicus)—one of the most important acridid pests. This means during joint outbreaks these two species can simultaneously damage almost all spectrum of plants.

Monitoring of damage and distribution of invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on maize crop in Karo, North Sumatera, Indonesia

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an invasive pest from America and has recently become an important pest in Indonesia. In their new environment, these pests have very high migratory and adaptive skills, as well as aggressive feeding habits. The aim of this research was to monitor the distribution, percentage of attacks, and damage caused by S. frugiperda on maize fields in the Karo District of North Sumatra Province. The study was conducted using a survey method at various altitudes and the sample unit was determined using the diagonal method. Each sample unit has a size of 2 × 2 m2. The age of maize crop used as the sample is 2-4; 5-6; 7-8; 9-10; and 11 weeks after planting (wap). Symptoms of attack, number of larvae population, and percentage of FAW attack were observed directly on plants. The results showed that FAW spread evenly at various altitudes, with the highest population at an altitude of 500-1,000 m.a.s.l at the age of 2-4 wap with a larval population density of 14.20 individual/unit sample. The highest percentage of attack was found at an altitude of 500-1,000 m.a.s.l, namely 82% at 2-4 wap. The highest attack on leaves occurred at an altitude of 500-1,000 m.a.s.l (70.6%) at the age of 2-4 wap.

Kepadatan populasi dan waktu efektif pelepasan tungau predator Neoseiulus longispinosus Evans untuk pengendalian Tetranychus kanzawai Kishida

Kanzawa spider mite, Tetranychus kanzawai Kishida (Tetranychidae) is one of the most important pest mite in Indonesia. This mite is known as the pest of many crops, including cassava. Neoseiulus longispinosus Evans (Phytoseiidae) is a predatory mite commonly found on plant infested by kanzawa spider mite. This predatory mite has high potential to be developed as biological control agent of T. kanzawai. The aim of this research is to elucidate the effective density and release time of N. longispinosus to control T. kanzawai on cassava. The research was conducted in the greenhouse, using cassava of Mentega cultivar. T. kanzawai were introduced into the cassava plants two weeks after planting, with density 5 female adults/plants. N. longispinosus were introduced 1, 2, and 3 weeks after T. kanzawai introduction with predator:prey ratio of 0:5, 1:5, 2:5, dan 3:5, respectively. Population of T. kanzawai and N. longispinosus, and also plant damage were observed at 6 weeks after planting. N. longispinosus could suppress T. kanzawai population and the highest suppression occurred at the interaction between 3:5 ratio and the release time at one week after T. kanzawai infestation. There was no significant effect of N. longispinosus release at various release ratio and time on attack intensity of T. kanzawai.

Natural Coinfection between Novel Species of Baculoviruses in Spodoptera ornithogalli Larvae

Spodoptera ornithogalli (Guenée) (Lepidoptera: Noctuidae) is an important pest in different crops of economic relevance in America. For its control, strategies that include chemicals are usually used; so, the description of entomopathogens would be very useful for the formulation of biopesticides. In this regard, two different baculoviruses affecting S. ornithogalli were isolated in Colombia, with one of them being an NPV and the other a GV. Ultrastructural, molecular, and biological characterization showed that both isolates possess the 38 core genes and are novel species in Baculoviridae, named as Spodoptera ornithogalli nucleopolyhedrovirus (SporNPV) and Spodoptera ornithogalli granulovirus (SporGV). The bioassays carried out in larvae of S. ornithogalli and S. frugiperda showed infectivity in both hosts but being higher in the first. In addition, it was observed that SporGV potentiates the insecticidal action of SporNPV (maximum value in ratio 2.5:97.5). Both viruses are individually infective but coexist in nature, producing mixed infections with a synergistic effect that improves the performance of the NPV and enables the transmission of the GV, which presents a slowly killing phenotype.

Ultrastructure of the Sensilla on the Antennae and Mouthparts of Bean Weevils, Megabruchidius dorsalis (Coleoptera: Bruchinae)

Megabruchidius dorsalis (Fåhraeus, 1839) (Coleoptera: Bruchinae) is an important pest that damages the seeds of Gleditsia L. (Fabaceae: Caesalpinioideae). This beetle searches for host plants with its sensory system. To further explore the mechanisms of host location and to understand the ultrastructure of M. dorsalis, we examined the morphology and distribution of its sensilla on the antennae and mouthparts of male and female adults, using scanning electron microscopy (SEM). Both male and female antennae are serrated and can be divided into scape, pedicel, and flagellum. There were seven types and eight subtypes of antennal sensilla, including Bőhm bristles (BB), two subtypes of sensilla trichoid (ST1, ST2), two subtypes of sensilla chaetica (SC1, SC2), four subtypes of sensilla basiconic (SB1, SB2, SB3, SB4), sensilla cavity (SCa), sensilla auricillica (SA), and sensilla gemmiformium (SG). Five types of maxillary and labial palp sensilla in the mouthparts were observed: sensilla chaetica (SC), sensilla trichoidea (ST), sensilla styloconica (SSt), sensilla coeloconica (SCo), and sensilla digitiform (SD). No sexual dimorphism in sensilla type was observed, but there were variations between males and females in the numbers and distribution along the antennae. There were more SA in males than in females, while the number of ST sensilla in the maxillary palps were lower in males than in females. ST1 were most abundant in both sexes. We discussed potential function related to structure via comparisons with previous investigations of bruchids and other insects. Our results provide a theoretical basis for further studies on sensory physiological function, using semiochemicals as effective biological controls of M. dorsalis.

Brown Marmorated Stink Bug (Halyomorpha halys Stål.) Attack Induces a Metabolic Response in Strawberry (Fragaria × ananassa Duch.) Fruit

The polyphagous brown marmorated stink bug (Halyomorpha halys Stål.) is an important pest in many countries. Recently it was noticed that it can feed on and cause damage to strawberries (Fragaria × ananassa Duch.). The metabolic response of strawberries to brown marmorated stink bug attacks was studied. Brown marmorated stink bugs attacked strawberry fruit which had 18% lower total sugar content compared to that of the control treatment. However, organic acid content had no significant difference among the three treatments, with the exception of shikimic acid, which had the highest content in the attacked fruit. Thirty-one phenolic compounds were identified. Results showed a strong effect on secondary metabolites due to H. halys attacks. Halyomorpha halys treatment had 27% higher total analyzed phenolic content compared to the indirect Halyomorpha halys treatment. The brown marmorated stink bug significantly increased total ellagic acid derivatives (33.1% to 37% higher), hydroxycinnamic acids (22.3% higher) and anthocyanins’ (39% higher) contents. Fruit attacked by Halyomorpha halys also had higher catechin and epicatechin content than that of the control treatments. This pest had a significant influence on the plant’s secondary metabolism, and this improved our understanding of how a strawberry plant reacts to the attacks of this very important pest. H. halys-infested fruit are not suitable for commercial production, due to the production of off-flavors.

Control Efficiency and Mechanism of Spinetoram Seed-Pelleting Against the Striped Flea Beetle Phyllotreta Striolata

The striped flea beetle (SFB, Phyllotreta striolata) is an important pest of the cruciferous crops in Asia. SFB is regarded as the most destructive pest of cruciferous crops in China due to the severe crop loss and frequent infestation incidents. As no SFB resistant cultivar is available at present, therefore, application of insecticides is the primary method of SFB control. On the contrary, the exploitation of chemical insecticides causes severe environmental issues and is not cost-effective. The use of a seed-pelletized coating of spinetoram effectively reduced SFB feedings on the flowering cabbage seedlings, whereas in combination with the insect-proof net, it controlled the SFB infestation throughout the cabbage growth period. The analysis of the pesticide residues in soil and different cabbage parts indicated the degradation dynamics of spinetoram. Furthermore, estimation of the half-life of spinetoram revealed that via seed-palletized application spinetoram half-life was found to be 2.82 days in soil, 4.21 days in the root, 5.77 days in the stem, and 3.57 days in the leaf, respectively. Both the lower pesticide residues and the half-life of spinetoram in soil and cabbage parts suggested it to be a promising environment and food-safe pesticide in controlling SFB. Moreover, the seed-pelletized coating ensured a sustainable release of spinetoram that can reduce the pesticide application frequency and be cost-effective and pocket-friendly for the farmers.