Within-plant distribution of cotton aphid (Hemiptera: Aphididae) in cotton cultivars with colored fibers

Abstract

We describe the vertical and horizontal distribution of the cotton aphid Aphis gossypii Glover within a cotton plant in two cotton (Gossypium hirsutum Linnaeus) cultivars (BRS Safira and BRS Rubí) with colored fiber over the time. Measurements of aphid population dynamics and distribution in the cotton plants were recorded in intervals of seven days. The number of apterous or alate aphids and their specific locations were recorded, using as a reference point the location of nodes on the mainstem of the plant and also those on the leaves present on branches and fruit structures. The number of apterous aphids found on the cultivar BRS Safira (56,515 aphids) was greater than that found on BRS Rubí (50,537 aphids). There was no significant difference between the number of alate aphids found on the cultivars BRS Safira (365 aphids/plant) and BRS Rubí (477 aphids/ plant). There were interactions between cotton cultivar and plant age, between plant region and plant age, and between cultivar and plant region for apterous aphids. The results of this study are of great importance in improving control strategies for A. gossypii in the naturally-colored cotton cultivars BRS Safira and BRS Rubí.

The Biology and Thermal Requirements of the Fennel Aphid Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae)

“…Little is known about the thermal tolerance of H. foeniculi or the bioecology of this aphid [13], yet this information could allow us to optimize control strategies. Therefore, the aim of this study was to investigate the biological responses of H. foeniculi to different temperatures and determine its thermal requirements under laboratory conditions.…”

The behavior of Aphis gossypii and Aphis craccivora (Hemiptera: Aphididae) and of their predator Cycloneda sanguinea (Coleoptera: Coccinellidae) in cotton-cowpea intercropping systems

“…Cotton (Gossypium hirsutum L.) cultivars with naturally colored fibers now have worldwide demand in the textile industry and have added value to the crop for small farmers (Fernandes et al 2012a, Ramalho et al 2012a. Cowpea (Vigna unguiculata L.…”

“…However, Aphis gossypii Glov. (Fernandes et al 2012a) and Aphis craccivora K. (Hemiptera: Aphididae), respectively, have been reducing cotton cowpea production in Brazil. These aphids cause direct damage by sucking sap and indirect ones by virus transmittion and excreting honeydew 374 FRANCISCO S. FERNANDES et al that favors the proliferation of leaf stomataobstructing fungi (Capnodium spp) (Kitajima et al 2008, Fernandes et al 2012a, 2013, Bachmann et al 2014, Malaquias et al 2014.…”

“…Aphis gossypii damages cotton plants during both vegetative and reproductive stages (Ramalho et al 2012a, Fernandes et al 2012b) and many plant species including eggplants and okra (Leite et al 2006(Leite et al , 2007. Infestation in vegetative stages turn leaves shriveled, whereas infestation in reproductive stages, especially at fruit opening, fouls and reduces fiber quality (Almeida 2001).…”

“…Agro-ecosystem diversification through intercropping may reduce insect pest infestations without the negative impacts of chemical measures (Gonzaga et al 1991, Medeiros et al 2009, Fernandes et al 2012c, Ramalho et al 2012a. The possibility of intercropping colored fiber cotton with fennel (Foeniculum vulgare Mill.)…”