Brassica aphid (Hemiptera: Aphididae) populations are conditioned by climatic variables and parasitism level: a study case of Triângulo Mineiro, Brazil

Abstract

Cosmopolitan pests such as Brevicoryne brassicae, Lipaphis pseudobrassicae, and Myzus persicae (Aphididae) cause significant damage to Brassicaceae crops. Assessment of the important biotic and abiotic factors that regulate these pests is an essential step in the development of effective Integrated Pest Management programs for these aphids. This study evaluated the influence of leaf position, precipitation, temperature, and parasitism on populations of L. pseudobrassicae, M. persicae, and B. brassicae in collard greens fields in the Triângulo Mineiro region (Minas Gerais state), Brazil. Similar numbers of B. brassicae were found on all parts of the collard green plants, whereas M. persicae and L. pseudobrassicae were found in greatest numbers on the middle and lower parts of the plant. While temperature and precipitation were positively related to aphid population size, their effects were not accumulative, as indicated by a negative interaction term. Although Diaeretiella rapae was the main parasitoid of these aphids, hyperparasitism was dominant; the main hyperparasitoid species recovered from plant samples was Alloxysta fuscicornis. Parasitoids seem to have similar distributions on plants as their hosts. These results may help predict aphid outbreaks and gives clues for specific intra-plant locations when searching for and monitoring aphid populations.

Contributions of climate, plant phenology and natural enemies to the seasonal variation of aphids on cabbage

“…In order to minimize interspecific competition, they present different plant colonization strategies. Brevicoryne brassicae prefers feeding the head leaves, whereas L. erysimi and M. persicae are mainly found in the medium and low leaves (Nematollahi, Fathipour, Talebi, Karimzadeh, & Zalucki, ; Sampaio et al, ). Population peaks of the aphids (especially L. erysimi ) were frequent during the evaluation period, indicating that cabbage growers should perform sampling throughout the year and do not rely on calendar application of insecticides.…”

Palaearctic species of Charipinae (Hymenoptera, Figitidae): two new species, synthesis and identification key

“…They have an adverse effect on the performance of the primary parasitoids by decreasing their abundance and modifying their behaviour (Sampaio et al 2017). Host specificity of these hyperparasitoids is still under debate, and for many Charipinae species very little is known about their trophic relationships.…”

Diversidad de parasitoides primarios y secundarios del pulgón Myzus persicae (Hemiptera, Aphididae) en el duraznero Prunus persica (Rosales, Rosaceae) en la provincia de Mendoza, Argentina

“…Con respecto al hiperparasitoidismo, estudios de Walgenbach (1994), Acebes and Messing (2013), Prado et al (2015) y Sampaio et al (2017) determinaron que los hiperparasitoides limitaron la eficiencia de los parasitoides primarios (entre los que se cuenta la especie A. colemani) en el control biológico de M. persicae y otros áfidos por su elevado porcentaje. En el presente trabajo pudimos observar que el desempeño de los parasitoides primarios probablemente se vio afectado principalmente en el mes de noviembre, época de emergencia común de parasitoides primarios y secundarios.…”