This research investigated the phenology of the striped flea beetle (Phyllotreta striolata (Fabricius) (SFB) and crucifer flea beetle (Phyllotreta cruciferae (Goeze)) (CFB), and examined the efficacy and the persistence of biological activity of the reduced-risk insecticides cyantraniliprole, clothianidin, and thiamethoxam applied as seed treatments to spring canola. Yellow sticky cards were placed around field perimeters in order to assess if CFB and SFB have synchronous phenology. It was found that CFB and SFB have largely asynchronous populations in southern Ontario. In laboratory bioassays, while flea beetle control with cyantraniliprole was comparable to that provided by thiamethoxam or clothianidin at the cotyledon stage, control did not persist through the 1st and 2nd leaf stages. Thiamethoxam and clothianidin both provided moderate control of flea beetles in both 1st and 2nd leaves. Field studies suggested that cyantraniliprole may offer control of flea beetles comparable to that provided by thiamethoxam and clothianidin. / E.I. DuPont Canada Co.

No description available.

Intercropping systems offer potential benefits relative to monocultures of increased crop yields and improved pest control through physical, chemical, or behavioural interference and the enhancement of natural enemy populations, prompting increased predation and parasitism. Intercrops of canola (Brassica napus L.) and wheat (Triticum aestivum L.) in various proportions were investigated at three sites in Alberta, Canada, in 2005 and 2006, to determine effects on 1) agronomic parameters, including crop grain and biomass yields, crop quality (canola oil and canola and wheat protein), lodging, soil microbial communities, and wheat leaf diseases; 2) pest insects, including flea beetle (Phyllotreta spp.) (Coleoptera: Chrysomelidae) damage to seedling canola and root maggot (Delia spp.) (Diptera: Anthomyiidae) adult collection numbers, egg populations, and canola taproot damage; and 3) beneficial insects, including ground beetles (Coleoptera: Carabidae) and the predator-parasitoid Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae). Crop yields were similar in intercrops and monocultures, and benefits of intercropping were observed in enhanced crop quality characteristics in some site-years. Neither soil microorganisms nor wheat leaf diseases generally responded to intercropping regimes. Intercropping did not reduce flea beetle damage to canola seedlings. Flea beetle damage was greatest at the first true-leaf stage of canola development. Although a thiamethoxam seed treatment reduced flea beetle herbivory, untreated plots generally did not sustain greater than 20% damage, suggesting that seed treatments were usually unnecessary. Adult Delia did not respond to intercropping canola with wheat, but egg populations were lower in intercrops on a land area basis. Canola taproot damage was as much as 13% reduced in intercrops compared to monocultures. Carabid beetles appeared to respond to qualities of the intercrops and monocultures, such as ground cover, rather than to the level of vegetational diversity itself, but carabid diversity was enhanced in diverse intercrops compared to canola monocultures in one site-year. Aleochara bilineata adult populations and parasitism rates were favoured in canola monocultures, but a temporal shift in A. bilineata adult collection numbers suggests reduced preference for canola monocultures in early summer. Benefits of canola-wheat intercrops identified in this study do not appear sufficient to recommend these cropping systems for widespread adoption in western Canada. / Plant Science

Pheromone lures and trap crops are appealing pest management tools that use insect and/or plant volatiles to reduce pest populations on crops of interest. Generating pheromone-emitting trap plants may allow for a continuing and highly-specific attraction of insect pests without repeated and costly application of synthetic pheromones. These trap plants may also be used to develop area-wide pest management strategies. As a proof-of-principle study we tested the possibility of producing the pheromone of the crucifer flea beetle Phyllotreta cruciferae in transgenic plants. P. cruciferae is an important pest of Brassica crops. In the presence of a host plant, males emit an aggregation pheromone, which attracts both males and females. Himachaladiene, a sesquiterpene, has been identified as a key component of the aggregation pheromone of P. cruciferae. In a close relative, Phyllotreta striolata, the compound is synthesized by a two-step pathway with an isoprenyl diphosphate synthase (PsIDS3) making (Z,E)-farnesyl diphosphate (FPP), which is converted by a terpene synthase (PsTPS1) to himachaladiene. Transient transformation of N. benthamiana with PsIDS3-TPS1 co-localized to the plastid resulted in the emission of himachaladiene and other known PsTPS1 products. Daily emissions of himachaladiene were approximately 1 µg per plant, which is six-fold higher than emissions from individual male flea beetles. Stable transformation of Arabidopsis thaliana with the same vector construct resulted in transgenic plants that expressed PsTPS1 and PsIDS3 transcripts, but no himachaladiene or other PsTPS1 products were present in volatile collections or leaf extracts of these plants. Moreover, no PsTPS1 enzyme activity was observed, indicating that post-transcriptional/translational effects prevent proper expression or targeting of functional PsIDS3 and/or PsTPS1 proteins in A. thaliana. Overall, this study demonstrates that the key component of the P. cruciferae aggregation pheromone, himachaladiene, can be transiently produced and emitted in a plant system at rates that are biologically relevant for insect attraction. However, further work is required for the stable production of the pheromone in plants. In addition, preliminary results are presented for the development of simple two-choice arenas that may allow for assessment of the movement of beetles toward host plant leaf tissue. This work can inform future efforts in developing methods for the economic production of himachaladiene in a plant system or the establishment of transgenic plants for the production and deployment of himachaladiene in a field setting. / Master of Science / The crucifer flea beetle is an important pest of vegetable and oilseed Brassica crops such as broccoli, cabbage and canola. Feeding by beetles has its greatest impact on crop health and yield in the early spring, when adult beetles emerge from overwintering sites and feed on newly- emerging Brassica seedlings. Currently these insects are controlled using broad spectrum insecticides. A general awareness of the negative aspects of insecticides drives the search for alternative pest management strategies that could diversify our management strategies and reduce reliance on insecticides. Previous work has found that the crucifer flea beetle navigates to its host plants, in part, through plant-emitted volatiles. After locating the plant host, males emit a volatile aggregation pheromone that when blended with host plant volatiles increases attraction. Here work towards the development of a specialized trap crop is presented. Plants were engineered to emit a key component of the crucifer flea beetle aggregation pheromone. In an engineered non-host plant, Nicotiana benthamiana, transient production of the aggregation pheromone was established. However, in an engineered Brassica plant, Arabidopsis thaliana, no aggregation pheromone was detected despite evidence of the presence and expression of the required biosynthetic genes for its production. A discussion on alternative engineering strategies for A. thaliana is presented. In addition, preliminary results are presented for the development of a simple behavior assay to assess the attraction of beetles toward different smells. This work can inform future efforts aimed at developing methods for the economic production of the aggregation pheromone in a plant system or the establishment of plants for the production and deployment of the aggregation pheromone in a field setting.

Flea beetles (FB), (Coleoptera: Chrysomelidae), are common pests of cabbage and eggplant, but little is known about the FB populations in Virginia, their impact on yield, or the most effective control methods. This research investigates the FB populations and impact of their feeding injury on cabbage and eggplant in Southwest Virginia, and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers. Crucifer flea beetle, Phyllotreta cruciferae (Goeze), and striped flea beetle, Phyllotreta striolata Fabr. were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) were found on eggplant. To evaluate the impact of FB feeding on these plants, insecticides were used to create a range of pest pressure. Flea beetle densities and defoliation was visually assessed weekly and individual plant as well as whole plot yields assessed at harvest. In both crops, as little as 20% defoliation significantly reduced yield, with higher defoliation resulting in lower yield. The efficacy of various insecticides was also evaluated; soil application of the systemic neonicotinoid dinotefuran had the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, deltamethrin-incorporated mesh row covers were evaluated and shown to provide excellent control of FB compared to an untreated row cover or a control; and comparable to the standard insecticide, dinotefuran. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them. / MSLFS / Flea beetles are tiny leaf-chewing pests of vegetables, particularly cabbage and eggplant. High populations of FB chewing on leaves can kill plants in early stages of development, and insecticides are the most common defense. Little is known about which FBs are in Virginia, their effect on vegetables grown in the state, or what the best way of controlling these pests. This research investigates FBs to determine the how they affected yield of cabbage and eggplant in Southwest Virginia, as well as determine the best methods for controlling these pests. Cabbage and eggplant were sampled weekly throughout two seasons, and two species were found on cabbage, the crucifer flea beetle and the striped flea beetle, whereas the eggplant flea beetle and the tobacco flea beetle were found on eggplant. To evaluate FB damage on these plants, defoliation of leaves was evaluated then yield was assessed. In both crops as little as 20% defoliation reduced yield, with higher defoliation resulting in lower yield of surviving plants. Various insecticides were evaluated to determine which treatment and application method were the most effective for controlling FB. A soil-applied systemic insecticide, dinotefuran, had the lowest density of beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, insecticide treated mesh row covers were evaluated and shown to be an effective method for controlling flea beetles on these crops. Treated row covers reduced FB numbers and feeding damage on these crops when compared to an untreated row cover. This research can benefit vegetable growers by helping them understand the severity of these pests and by providing effective management strategies to combat them.

No description available.