Effect of Cover Crops on Aphids, Whiteflies, and Their Associated Natural Enemies in Organic Squash

Effect of Cosmos, Crotalaria, Foeniculum, and Canavalia species, single-cropped or mixes, on the community of predatory arthropods

Some plants can attract natural enemy by offering resources such as alternative food and refuge. However, studies need to be conducted before agricultural landscape diversification is implement. Our objective was to determine the best floristic compositions of cosmos (Cosmos sulphureus—Asteraceae), showy rattlepod (Crotalaria spectabilis—Fabaceae), fennel (Foeniculum vulgare—Apiaceae), and jack bean (Canavalia ensiformis—Fabaceae) to attract and maintain predatory arthropods, and know the potential of these treatments for future use in diversifying agricultural systems. The experimental design consisted in seven treatments of four species in single-crop, intercrops in three densities called mix1, mix2, and mix3, and the control (weeds). For the arthropod families classified as very frequent and constant, population dynamics in intercropping treatments was plotted according to the plant phenology. We conclude that all plants cultivated in single-cropping and intercropping treatments showed high predator richness and can potentially be used to diversify cultivated areas. Sulfur cosmos as a single crop and three mixes attracts higher numbers and greater family richness. Spider families—Oxyopidae, Araneidae and Thomisidae—and insects—Chrysopidae and Coccinellidae are more frequents. The dynamics of the predator populations varied according to the mixes treatment.

Combining Cultural Tactics and Insecticides for the Management of the Sweetpotato Whitefly, Bemisia tabaci MEAM1, and Viruses in Yellow Squash

The sweet potato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN significantly reduced whiteflies and virus incidence on squash seedlings in the greenhouse study. In the field mulch study, lower whitefly abundance and SSL intensity, as well as reduced virus symptom severity, were observed in plots with reflective mulch compared with white plastic or live mulch. In the insecticide/row cover study, whitefly abundance, SSL intensity, and virus symptom severity were lowest in the row cover and cyantraniliprole- and flupyradifurone-treated plots. Field plots with row covers and those with UV-reflective mulch consistently produced the greatest marketable yields. These findings demonstrate that growers can reduce whitefly and virus pressure and preserve yields in squash production in the southeastern United States by combining cultural and chemical tactics, including row covers, UV-reflective mulch, and select insecticides.

The Effect of Summer Cover Crops and Strawberry Cultivars on the Twospotted Spider Mite, Tetranychus urticae (Acari: Tetranychidae) and the Predatory Mite, Neoseiulus californicus (Acari: Phytoseidae) in Organic Strawberry Production Systems in Florida

The twospotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), is a key pest of strawberries and many other crops worldwide. Cover cropping, selecting tolerant or resistant cultivars, and biological control are important strategies of an organic management plan. In this study, we examined the effect of summer cover crops and strawberry cultivars on populations of T. urticae and a commercially available predatory mite, Neoseiulus californicus McGregor (Acari: Phytoseiidae), commonly used for T. urticae management in Florida. In the 2013-2014 season, four cover crops and eight strawberry cultivars were screened at the research station and on a commercial organic strawberry farm. The following season, the most promising cover crops (sunn hemp and hairy indigo) and cultivars, 'Sensation', 'Strawberry Festival', and 'Winterstar' were tested at the research station and on two small organic farms. In the 2016-2017, 2017-2018, and 2018-2019 seasons, a 4-way mix of cover crops was compared to sunn hemp and hairy indigo. In 2016-2017, 'Florida Radiance' was added to the three previously selected cultivars. 'Florida Beauty' replaced 'Strawberry Festival' in 2017-2018 and 2018-2019, and 'Florida Brilliance' replaced 'Winterstar' in 2018-2019. The effects of summer cover crops on both T. urticae and N. californicus were minimal. 'Florida Brilliance', 'Florida Radiance', 'Sensation', 'Strawberry Festival', and 'Winterstar' had lower T. urticae populations and higher yields in most seasons at most locations. The establishment and abundance of N. californicus was similar on these cultivars and was generally higher where T. urticae populations were higher. Implications for organic strawberry production in Florida are discussed.

Effect of Cultural Practices on Neopamera bilobata in Relation to Fruit Injury and Marketable Yields in Organic Strawberries

Simple Summary

The strawberry seed bug is a native insect that has recently been causing injury to strawberries in Florida. This study examined the effects of two common cultural practices on the strawberry seed bug: cover cropping and runner removal. Cover cropping is used only in organic strawberry production while runner removal is common to both production systems. The effects of cultivar were also examined. Lastly, small bags were tied around strawberry fruits and different numbers of nymphal and adult seed bugs were released into the bags to examine the effects of their feeding on strawberry fruits. The use of cover crops did not impact seed bug populations. The results for runner removal were inconsistent but it was clear that removing runners does not increase seed bug populations or their injury to fruit. The cultivar “Florida Brilliance” received less injury likely because its seeds are recessed in the flesh of the fruit, making them more difficult for seed bugs to access. Both adults and nymphs caused injury to ripe fruit. Adults did not feed on unripe fruit, so injury to unripe fruit is likely caused by nymphal feeding.

Abstract

The strawberry seed bug, Neopamera bilobata (Say), is an emerging pest of organic and conventional strawberries in Florida. There is limited information on this Rhyparochromidae species. Thus, the type of injury caused is not clearly documented and management recommendations are lacking. In this study, we evaluated the effect of strawberry cultivars, cover crops, and the presence of runners on N. bilobata populations and yield. We also investigated the effect of select cultivars and the presence of runners on N. bilobata injury levels. In addition, we used fruit bagging experiments to investigate the effects of N. bilobata population and life stage (nymph vs. adult) on strawberry fruits. There was no effect of cover crop or cultivar on N. bilobata populations. In the 2017–2018 season, strawberry plots with runners contained higher N. bilobata populations compared with plots without runners, and adult infestation was significantly higher than nymphal infestation. In the 2018–2019 season, the trend was reversed with higher numbers of N. bilobata collected in plots with runners removed. In the 2019–2020 season, there was no significant difference in N. bilobata populations in plots with and without runners. In both 2018–2019 and 2019–2020, nymphal infestation was higher than adult infestation. Less injury was recorded in “Florida Brilliance” compared with the other cultivars tested. In the 2019–2020 season, less injury was recorded from plots without runners while the difference was not significant in 2017–2018 or 2018–2019. Releasing five and ten adult N. bilobata on ripe (red) fruit produced a similar level of injury while no injury to unripe (green) fruit was observed. Both adults and nymphs cause injury to ripe fruit. These findings can help contribute to the development of an integrated pest management program for strawberry N. bilobata.