Explore the vast range of titles available.

An increase in Spodoptera species was reported in Bt soybean fields expressing Cry1Ac insecticidal proteins in Brazil, requiring additional management with chemical insecticides. Here, we evaluated the dose effects of flubendiamide and thiodicarb on Spodoptera cosmioides (Walker, 1858), Spodoptera eridania (Stoll, 1782), Spodoptera albula (Walker, 1857) and Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) that survived on MON 87751 × MON 87708 × MON 87701 × MON 89788, expressing Cry1A.105, Cry2Ab2 and Cry1Ac; MON 87701 × MON 89788 soybean, expressing Cry1Ac; and non-Bt soybean. On unsprayed Cry1A.105/Cry2Ab2/Cry1Ac soybean, only S. frugiperda showed ~60% mortality after 10 d, whereas S. cosmioides, S. eridania and S. albula showed >81% mortality. The surviving larvae of all species on this Bt soybean showed >80% mortality when exposed to the field label dose of flubendiamide (70 mL/ha) or thiodicarb (400 g/ha) or at 50% of these doses. In contrast, all four species had <25% and <19% mortality on Cry1Ac and non-Bt soybean, respectively. The surviving S. cosmioides, S. eridania and S. albula on these soybean types presented >83% mortality after exposure to both dose levels of flubendiamide and thiodicarb. Some S. frugiperda larvae surviving on Cry1Ac and non-Bt soybean sprayed with a 50% dose of either insecticide developed into adults. However, the L1 larvae developing on Cry1Ac soybean leaves sprayed with flubendiamide and the L2 larvae on this soybean sprayed with thiodicarb had a prolonged immature stage, and the females displayed lower fecundity, which are likely to impact S. frugiperda population growth on soybean.

Genetically modified (GM) soybeans expressing Cry1A.105/Cry2Ab2/Cry1Ac (event MON 87701 × MON 89788 × MON 87751 × MON 87708) and Cry1Ac (event MON 87701 × MON 89788) from Bacillus thuringiensis Berliner (Bt) are valuable technologies for managing key lepidopteran pests of soybean in South America, but do not provide stand-alone protection against Spodoptera species. Here, we evaluated the use of these Bt soybeans and their integration with insecticides for managing Spodoptera species. Cry1A.105/Cry2Ab2/Cry1Ac soybean provided reasonable levels of protection against S. cosmioides, S. albula, and S. eridania. However, S. frugiperda had higher survival on this Bt soybean, and Cry1Ac soybean showed low lethality against all species evaluated. Spodoptera larvae that survived on Bt and non-Bt soybean showed comparable susceptibility to flubendiamide and thiodicarb in diet-overlay bioassays. Regardless of soybean plant type, the field doses of flubendiamide and thiodicarb were effective in controlling surviving Spodoptera larvae. We conclude that Cry1A.105/Cry2Ab2/Cry1Ac soybean is effective in controlling S. cosmioides and S. albula, and also has reasonable control of S. eridania, but not S. frugiperda. Cry1Ac soybean provided poor control of all Spodoptera species. Nonetheless, Spodoptera larvae surviving on both Bt and non-Bt soybean were controlled by flubendiamide and thiodicarb. Thus, integrated control tactics would provide effective management of Spodoptera species in Bt soybean fields in South America.

Winter moth, Operophtera brumata, native to Europe, invaded the northeastern United States in the late 1990s, where it caused widespread defoliation of forests and shade trees ranging from 2,266 to 36,360 ha/yr between 2003 and 2015 in Massachusetts. In 2005, we initiated a biological control effort based on the specialist tachinid parasitoid Cyzenis albicans, which had previously been introduced along with the generalist ichneumonid parasitoid Agrypon flaveolatum to control winter moth in Nova Scotia in the 1950s and British Columbia in the 1970s. Due to concerns of possible non-target impacts by A. flaveolatum, we focused entirely on the specialist C. albicans. Each year for 14 yr, we collected several thousand individuals of C. albicans from British Columbia and released them in widely spaced sites in the northeastern United States. As of 2020, we had established C. albicans at 41 of 44 sites from coastal Maine to southeastern Connecticut. By 2016, winter moth densities (pupae/m²) had declined from 100–500 to 0–10 pupae/m² at six release sites at least 10 km apart and this was coincident with the onset of 10–40% parasitism. At one site in Wellesley, Massachusetts, the decline occurred in 2012 and winter moth densities have remained low for seven subsequent years. Defoliation in Massachusetts has been reduced to undetectable levels by aerial survey since 2016. DNA sequencing of the barcoding region of the mitochondrial gene CO1 confirmed that all C. albicans reared from winter moth matched the C. albicans collected from Vancouver Island and were distinct from parasitic flies (presumably a native species) reared from a native congener of winter moth, Bruce spanworm (O. bruceata). Successful establishment of C. albicans on winter moth represents a rare, if not the only, example of the biological control of a major forest defoliator that attacks a wide range of tree species anywhere in the world by the establishment of a single specialist natural enemy.

Temperature provides important physiological constraints that can influence the distribution of an invasive species. Gypsy moth (Lymantria dispar L.) is a generalist defoliator in North America and supraoptimal temperatures (above the optimal for developmental rate) have been implicated in range dynamics at the southern invasion front in West Virginia and Virginia. We sourced egg masses from the Appalachian Mountains (AM), where the gypsy moth range is expanding, from the Coastal Plain (CP), where range retraction is occurring, and from a long-established population in New York (NY) and conducted a reciprocal transplant experiment to compare development and fitness components among these populations at two sites along the southern invasion front. We found evidence of sublethal effects from rearing in the CP, with decreased pupal mass and fewer eggs compared to individuals reared in the AM, but little difference between source populations in developmental traits. The AM and NY populations did experience reductions in egg viability under a southern winter at the CP site compared to control wintering conditions, while the CP egg masses had equivalent survival. This study provides empirical support for negative fitness consequences of supraoptimal temperatures at the southern range edge, consistent with patterns of range retraction and spread in the region, as well as suggesting the potential for local adaptation through variation in egg survival. Our work illustrates that sublethal effects from high temperature can be an important factor determining the distribution of invasive species under current and future climates.

Natural enemies that impact pest populations must be understood in order to build integrated pest control strategies and to understand the most important aspects affecting pest dynamics. Haloxylon ammodendron (C. A. Mey.) Bunge is an important perennial plant species extensively used in sand stabilization and wind prevention in arid areas. This study aimed to determine the main defoliators that damage H. ammodendron and the parasitoid complex associated with them. Twelve species of defoliators were found in Northern Xinjiang, and Teia dubia (Tauscher) (Lepidoptera: Lymantriidae), Scrobipalpa sp. (Lepidoptera: Gelechiidae), and Eucharia festiva Hüfnagel (Lepidoptera: Arctiidae) were the dominant pests. T. dubia is the predominant defoliator with three generations a year. Northwest China, Central Asia, and the Mediterranean region are potentially suitable habitats for T. dubia in the world, while Xinjiang is the primary distribution area in China. Parasitoids belonging to seven species and four families were reared from the larvae of T. dubia, they were all endoparasitoids and koinobiont. Cotesia sp. (Hymenoptera: Braconidae) is the dominant parasitoid and prefer to parasitic in the 3rd–5th instar larvae. The present study provides the basis for understanding the species composition and natural enemies of lepidopteran defoliators. It will be an effective tool for the integrated pest management programs of H. ammodendron forest.

About one third of North America is forested. These forests are of incalculable value to human society in terms of harvested resources and ecosystem services and are sensitive to disturbance regimes. Epidemics of forest insects and diseases are the dominant sources of disturbance to North American forests. Here we review current understanding of climatic effects on the abundance of forest insects and diseases in North America, and of the ecological and socioeconomic impacts of biotic disturbances. We identify 27 insects (6 nonindigenous) and 22 diseases (9 nonindigenous) that are notable agents of disturbance in North American forests. The distribution and abundance of forest insects and pathogens respond rapidly to climatic variation due to their physiological sensitivity to temperature, high mobility, short generation times, and high reproductive potential. Additionally, climate affects tree defenses, tree tolerance, and community interactions involving enemies, competitors, and mutualists of insects and diseases. Recent research affirms the importance of milder winters, warmer growing seasons, and changes in moisture availability to the occurrence of biotic disturbances. Predictions from the first US National Climate Assessment of expansions in forest disturbances from climate change have been upheld - in some cases more rapidly and dramatically than expected. Clear examples are offered by recent epidemics of spruce beetles in Alaska, mountain pine beetle in high-elevation five-needle pine forests of the Rocky Mountains, and southern pine beetle in the New Jersey Pinelands. Pathogens are less studied with respect to climate but some are facilitated by warmer and wetter summer conditions. Changes in biotic disturbances have broad consequences for forest ecosystems and the services they provide to society. Climatic effects on forest insect and disease outbreaks may foster further changes in climate by influencing the exchange of carbon, water, and energy between forests and the atmosphere. Climate-induced changes in forest productivity and disturbance create opportunities as well as vulnerabilities (e.g., increases in productivity in many areas, and probably decreases in disturbance risks in some areas). There is a critical need to better understand and predict the interactions among climate, forest productivity, forest disturbance, and the socioeconomic relations between forests and people.

Abstract Flighted spongy moth, Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky, is a highly destructive defoliator that threatens forest and urban trees in both its native Asian range and where introduced. This moth goes through outbreak periods with very high population numbers resulting in defoliation of almost all deciduous and coniferous trees and potentially severe human allergic reactions to the insect hairs and scales. Adult females are capable of strong ascending flight and at night are attracted to lights where they lay their egg masses on surrounding surfaces. This has resulted in flighted spongy moth hitchhiking multiple times to new areas as egg masses, or occasionally as pupae, on ships and their cargo. Flighted spongy moths have a broad host range that includes several hundred tree species, both broadleaf and conifer. Identification of stages and species, life history, and ecology are reviewed here. There are few biological differences between the 2 subspecies, but L. dispar japonica tends to be larger and flies at a slightly different time of day than L. dispar asiatica. Both eradication (in introduced areas) and management require detection which is primarily accomplished using male pheromone traps and egg mass surveys. Populations are controlled by various natural and managed methods including parasitoids, predators, pathogens, microbial pesticides registered for aerial and ground application, mating disruption (applying pheromone in various formulations), and aerially spraying insect growth regulators. Synthetic insecticides are rarely used due to public concerns regarding unintended nontarget impacts. Graphical Abstract Graphical Abstract

This study investigates spongy moth (Lymantria dispar) infestation patterns in Whirlpool Forest, Ontario, offering a region-specific perspective while largely corroborating existing findings. We analyzed egg mass distribution across 43 sampling plots, relating it to tree characteristics. Results revealed a preference for red oak species, with significant egg-laying above one meter. Positive correlations were found between tree diameter and egg mass quantity (ρ = 0.458, p < 0.001 above 1 m; ρ = 0.218, p = 0.006 below 1 m). Tree health was significantly associated with egg mass presence (χ2 = 6.08, p = 0.014). A climate-based regression model (R2 = 0.714, p < 0.05) projected substantial increases in outbreak area by 2100, with the most severe scenario predicting 9,927,378.49 hectares at risk. Sensitivity analysis showed a 1 °C temperature increase could expand the outbreak area by 814,100 hectares. These findings underscore complex infestation dynamics, challenging simplified models and emphasizing the need for tailored, adaptive forest management strategies in response to changing environmental conditions and pest behaviors.

Old-growth forests have become rare in North America but provide habitat for unique assemblages of species that often are rare in younger forests. Insects and related arthropods reach their highest diversity in old-growth forests because of their stable moderate temperature and relative humidity and the rich variety of resources represented by high plant species richness and structural complexity. Old-growth arthropod assemblages typically are distinct from those in younger, managed forests. Major subcommunities include the arboreal community that is composed of a rich assemblage of herbivores, fungivores, and their associated predators and parasitoids that function to regulate primary production and nutrient fluxes, the stem zone community that includes bark- and wood-boring species and their associated predators and parasitoids that initiate the decomposition of coarse woody debris, and the forest floor community composed of a variety of detritivores, fungivores, burrowers, and their associated predators and parasitoids that are instrumental in litter decomposition. Insect outbreaks are relatively rare in old-growth forests, where the diversity of resources and predators limit population growth. In turn, insects contribute to plant diversity and limit primary production of host plant species, thereby promoting development of old-growth forest characteristics. Arthropods also provide important functions in decomposition and nutrient cycling that may be lost in younger, managed forests with limited provision of coarse woody debris and accumulated litter. Protection of remnant old-growth forests within the forest matrix may be particularly valuable for maintaining the diversity of plant and arthropod predators that can minimize outbreaks, thereby contributing to resilience to changing environmental conditions.

Silver oak, Grevillea robusta A. Cunn. is an important exotic tree species component of urban forestry in India. However, the occurrence of insect-pests in exotics causes tremendous impact on the production and yield in nurseries as well-established plantations; consequently, reducing profits and inducing high expense to stakeholders. Thus, a detailed account of insect-pests infestation and their impact becomes important. Therefore, present study was undertaken to find out the insect pest occurrence on G. robusta in the nursery, plantation established at different geographical region of northern India from 2018-2022. The study result exhibited infestation of ten insect-pests for the first time on G. robusta. Six species were defoliator in nature viz. Ascotis selenaria, Chrysodeixis includens, Ectropis bhurmitra, Helicoverpa armigera, Hyposidra talaca, and Olene inclusa; while infestation of four species of sap sacking nature viz. Asterolecanium sp., Ceroplastes rusci, Drosicha stebbingi, and Oxyrachis tarandus. The seasonal incidence and nature of damage were also recorded for the first time of these insects on G. robusta. This is the first attempt to report insect-pests of G. robusta, which gave an overview of the possible potential threat in India. The study would be beneficial for future reference with respect to pest management of G. robusta, when the species is taken up for tree improvement program in the long run.