Impact of crimson clover dying mulch on two eggplant insect herbivores

Abstract

Eggplant Solanum melongena L., is often colonized by two early season insect defoliators. The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and flea beetles Epitrix spp., emerge from their overwintering sites in early spring and seek out emerging host plants such as eggplant. During the 2009 and 2010 growing season, field studies were conducted to investigate the impact of inter‐planting eggplant into a crimson clover (CC), Trifolium incarnatum L., winter cover crop on populations of flea beetles, CPB and their associated arthropod predators. The experiment consisted also of two levels of insecticide usage such as an application of azadirachtins plus pyrethrins followed by several applications of spinosad or no insecticide sprays as subplot treatments. During both study years, significantly fewer (adults, larvae and egg masses) were found on eggplant inter‐planted into CC than in bare‐ground (BG) eggplant plots. Although flea beetle abundance was greater in BG eggplant during 2010, they appeared to be less influenced by the presence of CC than were CPB. Additionally, there was no apparent impact of insecticide treatment on CPB populations on eggplant inter‐planted into CC. However, there was a decline in CPB following treatments with insecticides in BG eggplant plots. This suggests that a winter cover crop such as CC can be used to help manage CPB in eggplant, however, using this tactic in tandem with insecticide sprays may not result in greater CPB management.

Growth and yield of zucchini squash (Cucurbita pepoL.) as influenced by a sunn hemp living mulch

“…In a study conducted by Hooks et al (2013a), despite significant reduction in pest density and greater proportions of beneficial arthropods, yields of eggplant inter-planted into a mowed crimson clover companion planting were significantly lower than in monoculture eggplant (Hooks et 2013b). In a subsequent study, when alternate rows of crimson clover were strip-tilled as opposed to mowed, pest suppression was maintained and eggplant growth and yield was significantly enhanced in crimson clover compared with monoculture unsprayed eggplant plantings (Hooks et al 2013b).…”

“…Additionally, several studies have shown that the companion planting tactic can be effectively used to delay the onset of insect caused plant diseases and phytotoxemias in cucurbit crops (Frank & Liburd 2005;Nyoike et al 2008;Manandhar & Hooks 2011). Although companion plants have been found to reduce the occurrence of insect, disease and weed pests within cropping systems, they can compete with, and subsequently reduce, crop yields, thus making their use less practical (Vandermeer 1989;Walters & Young 2008;Hooks et al 2013a).…”

The effects of crimson clover companion planting on eggplant crop growth, yield and insect feeding injury

“…During both study years, significantly fewer CPB (adults, larvae and egg masses) were found on eggplant inter-planted into CC than in bare-ground (BG) eggplant plots; and although flea beetle abundance was greater in BG eggplant during year 2, they appeared to be less influenced by the presence of CC than were CPBs (Hooks et al 2012). These finding suggests that CC could be used to help manage CPB in eggplant.…”

“…Further, during sampling occasions this is consistently where flea beetles were found. The interest therefore was not to estimate or quantify the amount of damage throughout the whole plant, but to record the number of feeding pits displayed at the young terminal plant area during the early eggplant growth cycle when flea beetles were most abundant (Hooks et al 2012). Feeding injury was assessed weekly from 7 to 28 DAP.…”

“…), Japanese beetle (Popillia japonica Newman) and various species of flea beetles (Epitrix spp.) (Hooks et al 2012).…”