Since its introduction from Asia, the brown marmorated stink bug, Halyomorpha halys (Stål), has become a pest of many agricultural crops in the USA. Insect predators utilize H. halys as prey; however, the chemical cues used by them in prey location are largely unknown. Here, we hypothesized that tridecane, an H. halys-associated volatile, acts as a kairomone for the predaceous minute pirate bug, Orius insidiosus (Say). We conducted laboratory, greenhouse, and field experiments to: (1) assess the attraction of adult O. insidiosus to H. halys-damaged bean pods and tridecane in cage studies, and its effect on egg predation; (2) video record the behavioral response of O. insidiosus males and females to tridecane in a four-arm olfactometer; and (3) test whether Orius spp. are attracted to tridecane-baited sticky traps in peach, blueberry, and sunflower fields, and its effect on egg predation. In the greenhouse, O. insidiosus was attracted to H. halys-damaged pods and artificial plants baited with tridecane in the presence of prey (sentinel eggs); however, this attraction rarely led to increased egg predation. Although both O. insidiosus males and females spent more time in the arm of the olfactometer with tridecane, males were more responsive at a lower concentration than females. Similarly, Orius spp. were more attracted to tridecane-baited than unbaited traps in the field; however, there was no effect on egg predation. Altogether, while O. insidiosus is attracted to tridecane, this attraction did not always lead to higher predation, suggesting that this kairomone likely acts as an arrestant.
The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive pest from Asia that feeds on many agricultural crops in the United States, including blueberries. Yet, the effects of H. halys feeding on fruit chemistry and induced resistance to insects remain unknown. Here we hypothesized that frugivory by H. halys changes fruit chemical composition, which in turn affects insect feeding behavior. In field experiments, blueberry fruit was either mechanically injured or injured by 0 (control), 2, 5, or 10 H. halys Total soluble solids (°Brix) and anthocyanin and phenolic content in injured and uninjured fruits, as well as their effects on feeding behavior by conspecifics, were measured subsequently in the laboratory. Results showed lower °Brix values in injured fruit as compared with uninjured fruit. Fruit injured by 2 and 5 H. halys also had 32 and 20% higher total phenolics, respectively, than the uninjured controls. The proportions of the anthocyanins derived from delphinidin, cyanidin, and petunidin increased, whereas those from malvidin decreased, in fruit after mechanical wounding and frugivory by H. halys In dual-choice tests, H. halys fed more often on uninjured fruit than those previously injured by conspecifics. These results show that frugivory by H. halys reduces the amounts of soluble solids, alters anthocyanin ratios, and increases levels of phenolics, and, as a result, injured fruits were a less preferred food source for conspecifics. To our knowledge, this is the first study to investigate the effects of frugivory on fruit chemistry and induced fruit resistance against a fruit-eating herbivore.
Diverse plantings provide many benefits for agroecosystem health. For example, "trap crops" that are highly attractive to pests can protect nearby, less attractive host plants. However, it is unclear whether increasing biodiversity of trap crops themselves might increase the effectiveness of this pest management technique. We examined whether multi-species trap-crop plantings were more effective than any single species at protecting broccoli (Brassica oleracea var. italica) crops from the crucifer flea beetle, Phyllotreta crttciferae. Our trap crop plantings included between one and three plant species (Brassica juncea, Brassica napus, and/or Brassica rapa subsp. pekinensis), selected for their attractiveness to the beetles, while keeping total trap crop area constant. We found that only a diverse mix of all three trap crops significantly improved yields of adjacent broccoli; indeed, the 3-species polyculture provided protection that exceeded, that of a monoculture of the most effective single trap crop species. Furthermore, the protective effect of diverse trap crop plantings extended across the broccoli beds. Treating trap crops with an insecticide provided no further benefits for pest control or broccoli yields. Despite clear benefits of trap-crop diversity on yields, the number of flea beetles did not differ in broccoli adjacent to diverse versus simple trap crops, or in the trap-crops themselves. This suggests that plant protection resulted from a change in pest behavior rather than abundance. Our study revealed that increasing biodiversity of trap-crop plantings might be an effective means to enhance the success of the approach in many systems. (C) 2016 Elsevier B.V. All rights reserved.
The National Institute of Food and Agriculture within the U.S. Department of Agriculture provides leadership, capacity, and funds to support the continuing development of a safe and competitive agricultural system. Many of the agency’s educational programs are led by the Division of Community and Education (DOCE). These programs span agricultural education, enhancing agricultural literacy through both formal and nonformal education. Here, we have highlighted funding opportunities within DOCE that enhance agricultural education and literacy by supporting the improvement of students’ critical communication, leadership skills, and experiential learning opportunities. Some of these programs include opportunities for which students can apply, while others focus on faculty applications. Opportunities faculty can apply for may support student-recruitment and student-retention techniques, curriculum development, innovative teaching methods, and institutional capacity-building programs. Overall, these programs foster a diverse workforce in agricultural science that matches the increasing diversity of the country.
Brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a severe economic pest of growing importance in the United States, Canada, and Europe. While feeding damage from H. halys has been characterized in tree fruit, vegetables, and agronomic crops, less is known about the impacts of stink bugs on small fruits such as blueberries. In this study, we examined H. halys feeding on two representative early and late ripening blueberry cultivars in Oregon and New Jersey. This research examined how different densities of H. halys confined on blueberry clusters for week-long periods affected fruit quality at harvest. After fruit were ripe, we stained and quantified the number of salivary sheaths on berries as an indication of feeding pressure. Feeding by H. halys damaged the fruits by causing increased levels of external discoloration, and internal damage in the form of tissue necrosis. Exposure of berries to H. halys was also associated with decreasing berry weights and lower soluble solids in fruits. However, the different cultivars did not respond consistently to feeding pressure from H. halys. Weekly variability in feeding pressure of two of the cultivars as quantified by the number of stylet sheaths per berry was largely accounted for by environmental variables. We conclude that H. halys does have potential to severely damage blueberries and may become an important economic pest. Characterization of damage is important because correct identification of insect damage is key for successful management.
There is growing public concern about pesticides’ non-target effects on humans and other organisms, and many pests have evolved resistance to some of the most commonly-used pesticides. Together, these factors have led to increasing interest in non-chemical, ecologicallysound ways to manage pests [1]. One pest-management alternative is the diversification of agricultural fields by establishing “polycultures” that include one or more different crop varieties or species within the same field, to more-closely match the higher species richness typical of natural systems [2, 3]. After all, destructive, explosive herbivore outbreaks typical of agricultural monocultures are rarely seen in highly-diverse unmanaged communities.
A random amplified polymorphic DNA assay was used to assess genetic variation in populations of the seagrass Halodule wrightii (Ascherson) from the western Gulf of Mexico. This region includes one of the world's few hypersaline lagoons (Laguna Madre) and contains the vast majority of seagrasses on the Texas coast. Results indicate a moderate amount of genetic diversity among populations. The highest level (Hc= 0.33) was found in a population from Nueces Bay, a disturbed site in the Coastal Bend area, whereas the lowest was found in a Lower Laguna Madre population (Hc = 0.15). Genetic differentiation generally followed an isolation-by-distance model. The Nueces Bay population also showed the greatest degree of differentiation, whereas the Redflsh Bay and Lower Laguna Madre populations were relatively similar (φST = 0.091). Combined with previous results, we now have a rudimentary picture of genetic variation in this species from the Texas Gulf Coast.
The south Texas Gulf coast is a unique ecosystem that contains a number of different bay systems. We used random amplification of polymorphic DNA (RAPD) markers to assess genetic diversity, differentiation and genetic distance between populations from two different bays that differed significantly in terms of flowering rate and disturbance. We found that while each bay contained a number of unique RAPD profiles, the average genetic diversity in each population was low. Genetic distance between the two populations was also low (Fst=0.084) and the majority (92%) of the genetic variation was attributed to differences between individuals within populations. The population from the Laguna Madre location, however, was polymorphic for a larger number of markers, had a higher average genetic diversity and a larger number of unique RAPD profiles. The higher level of flowering at this location most likely accounts for the higher diversity.