Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2007
Publication Date: July 20, 2007
Citation: Showler, A.T., Armstrong, J.S. 2007. Kaolin particle film associated with increased cotton aphid infestations in cotton. Entomologia Experimentalis et Applicata. 124(1):55-60.
Interpretive Summary: Kaolin particle film has been reported as effective for protecting pest damage in a number of crops, but one study indicated that cotton aphid numbers increased where kaolin was sprayed. This study examined the effects on kaolin particle film application on leaf cotton aphid populations, as well as mechanisms, such as color, parasitism, and leaf temperature, that might explain the observed increases in populations. Although the color white does not attract cotton aphids more than green, and parasitism was unaffected, leaf temperature was lower on kaolin-treated cotton plants, and this was identified as the most likely cause of the difference in infestation.
Highly reflective white kaolin-based particle film was sprayed on cotton plots in south Texas in order to observe its effect on the cotton aphid, Aphis gossypii Glover. Populations of cotton aphids on the undersides of leaves in the kaolin treated plots were greater than in non-treated control plots during 2004 and 2005. This occurred in spite of our findings that alate cotton aphids were attracted less to white- to green-colored traps. Also, the incidence of parasitism was higher in the kaolin-treated plots during 2004 and differences were not detected in 2005. The temperature on the undersides of the kaolin treated cotton leaves, however, was cooler than in the control plots, a condition that is known to be more amenable to cotton aphid development and reproduction that warmer temperatures. Kaolin particle film can protect a variety of crops against selected pest arthropods, including aphids, but our study is the first to demonstrate that kaolin can exacerbate a pest infestation.