Summary Theory shows that fluctuation of environmental conditions can produce temporal niches for inferior competitors that mitigate effects of inter specific competition and facilitate long-term persistence of poor competitors.In south Florida the mosquitoes Aedes albopictus and Aedes aegypti often co-occur in water-filled containers despite A. albopictus being competitively superior to A. aegypti. We tested the hypothesis that seasonal fluctuation in environmental conditions reduces or reverses competitive asymmetry between the species, and contributes to persistence of the poorer competitor via stabilizing or equalizing effects.During the Florida wet and dry seasons we manipulated mosquito egg exposure to desiccation before inducing hatching and allowing surviving larvae to compete for 59 days. The effect of season also incorporated seasonal fluctuations in resource input to experimental containers.For both species composite index of population performance (λ’) was greater in the dry season than the wet season, indicating strong seasonal effects on population dynamics. Aedes albopictus was not affected by competition in either season. Aedes aegypti was negatively affected by interspecific competition in the wet season.Aedes aegypti egg survival was unaffected by exposure to the different experimental environments. There was a small reduction in A. albopictus egg survival in the wet season, but this reduction was unrelated to effects on λ’, indicating fluctuation in the egg environment did not contribute to dry season release from competition.Detritus resource inputs were over three times greater in the dry season than in the wet season. Given the relatively small effect of environment on egg survival these results suggest that seasonal differences in population performance are driven primarily by per-capita food availability.Large inputs of detritus in the dry season appear to reduce competition, and produce similar responses in both species. This result suggests that seasonal variation contributes to coexistence of A. albopictus and A. aegypti as a fitness equalizing factor.

Few studies have taken a comprehensive approach of measuring the impact of inter- and intra-specific larval competition on adult mosquito traits. In this study, the impact of competition Aedes aegypti and A. albopictus was quantified over the entire life of a cohort.Competitive treatments affected hatch-to-adult survivorship and development time to adulthood of females for both species, but affected median wing length of females only for A. albopictus. Competitive treatments had no significant effect on the median adult female longevity nor were there any effects on other individual traits related to bloodfeeding and reproductive success.Analysis of life table traits revealed no effect of competitive treatment on net reproductive rate (R0) but there were significant effects on cohort generation time (Tc) and cohort rate of increase (r) for both species.Inter-specific and intra-specific competition among Aedes larvae may produce individual and population-level effects that are manifest in adults; however, benign conditions may enable resulting adults to compensate for some impacts of competition, particularly those affecting blood feeding success, fecundity, and net reproductive rate, R0. The effect of competition, therefore, affects primarily larva – to - adult survivorship and larval development time, which in turn impact the cohort generation time, Tc and ultimately cohort rate of increase, r.The lack of effects of larval rearing environment on adult longevity suggests that effects on vectorial capacity due to longevity may be limited if adults have easy access to sugar and blood meals.

BACKGROUND: The flatheaded appletree borer (Chrysobothris femorata Olivier) (FHAB) is a native pest of fruit, shade and nut trees throughout the United States. Use of cover crops is an effective pest management tool for some key insect pests in vegetable and cereal production systems, but its impact in woody ornamental production systems has not been investigated. The goal of this study was to evaluate the effectiveness of a winter cover crop for management of FHAB in nursery production. Red maple trees (Acer rubrum L.) grown under four treatment regimes (cover crop, cover crop + insecticide, bare row and bare row + insecticide) were evaluated for damage by FHAB and impact on tree growth parameters. RESULTS:The cover crop reduced FHAB damage, with results equivalent to standard imidacloprid treatments. The reduction in FHAB attacks in cover crop treatments may be due to microclimate changes at preferred oviposition sites, trunk camouflage or interference with access to oviposition sites. Tree growth was reduced in the cover crop treatments due to competition for resources. CONCLUSION: Physical blockage of oviposition sites by cover crops and subsequent microclimate changes protected against FHAB damage. Therefore, cover crops can be an alternative to chemical insecticides.

Japanese maple scale, Lopholeucaspis japonica Cockerell (Hemiptera: Diaspididae), is an armored scale found on the bark of many woody nursery and landscape plants. Scale crawler and male flight activity was monitored in middle Tennessee in fields of cherry (Prunus serrulata Lindl. ‘Kwanzan’) for two seasons. Two generations of crawlers were observed, with a large peak of activity in late May and a second, less pronounced peak in August. Male flights occurred twice a year, in April and July. Spray and drench applications of insecticides were trialed in 2014 and 2015. Dormant oil applications reduced overwintering scale populations by 76%. Drench applications of imidacloprid in 2014 suppressed scale populations by 58% by four months following application and the following summer those same trees had no observable scale infestation. Summer trunk applications of pyriproxyfen were effective at managing scale crawlers while horticultural oil alone had no measurable effect. When scale populations were high at the outset of spring 2014, a dinotefuran drench application was ineffective after 90 days. Dinotefuran gave greater control in 2015 when scale populations were low prior to application. Based on these results, a multiple component program for field management of Japanese maple scale is recommended.

The majority of wood-boring ambrosia beetles are strongly attracted to ethanol, a behavior which could be exploited for management within ornamental nurseries. A series of experiments was conducted to determine if ethanol-based interception techniques could reduce ambrosia beetle pest pressure. In two experiments, trap trees injected with a high dose of ethanol were positioned either adjacent or 10-15 m from trees injected with a low dose of ethanol (simulating a mildly stressed tree) to determine if the high-dose trap trees could draw beetle attacks away from immediately adjacent stressed nursery trees. The high-ethanol-dose trees sustained considerably higher attacks than the low-dose trees; however, distance between the low-and high-dose trees did not significantly alter attack rates on the low-dose trees. In a third experiment, 60-m length trap lines with varying densities of ethanol-baited traps were deployed along a forest edge to determine if immigrating beetles could be intercepted before reaching sentinel traps or artificially stressed sentinel trees located 10 m further in-field. Intercept trap densities of 2 or 4 traps per trap line were associated with fewer attacks on sentinel trees compared to no traps, but 7 or 13 traps had no impact. None of the tested intercept trap densities resulted in significantly fewer beetles reaching the sentinel traps. The evaluated ethanol-based interception techniques showed limited promise for reducing ambrosia beetle pressure on nursery trees. An interception effect might be enhanced by applying a repellent compound to nursery trees in a push-pull strategy.