Evaluation of hydrophobic and hydrophilic kaolin particle films for peach crop, arthropod and disease management

Abstract

Hydrophobic and/or hydrophilic kaolin particle film treatments to peach (Prunus persica (L) Batsch) trees were evaluated for crop and pest management capabilities in six studies from 1997 to 2000. Unsprayed control and standard treatments, the latter consisting of a commercial pesticide program, were included for comparison. Treatments in initial studies were applied via handgun, which resulted in a uniform and heavy deposit of kaolin after the first application. In contrast, treatments in subsequent studies used airblast equipment, which provided a uniform but less dense coverage, even after multiple applications. Results showed that both formulations of kaolin provided control of oriental fruit moth (Grapholita molesta (Busck)), plum curculio (Conotrachelus nenuphar (Herbst)) and Japanese beetle (Popillia japonica Newman) that was comparable with or better than the standard pesticide program. Effective management of late season catfacing insects (tarnished plant bugs Lygus lineolaris (Palisot de Beauvois) and stinkbugs Acrosternum hilare (Say), Euschistus servus (Say), and E tristigmus (Say)) and leafrollers (undetermined species) was also observed, although kaolin applications significantly increased phytophagous mite (Panonychus ulmi (Koch)) levels. In contrast to arthropod management, kaolin failed to control either peach scab (Cladosporium carpophilum (Von Thumen)) or rusty spot (Podosphaera leucotricha (Ell and Ev) ES Salmon) in any of the 4 years of the study. However, hydrophobic kaolin provided effective brown rot (Monilinia fructicola (G Winter) Honey) control when applied via handgun, and partial control when applied via airblast; hydrophilic kaolin failed to provide any control. These results suggest that hydrophobicity and deposit density may be important factors for effective disease management. The application of kaolin significantly delayed fruit maturation, increased fruit size and increased soluble solids relative to the standard. This effect, attributed to a reduction in plant stress, also resulted in increased fruit number and yield on young trees, indicating that an accentuated beneficial response from kaolin applications may be possible.

Control of Plant Disease by Disguising the Leaf Surface

“…Whether or not kaolin particle fi lms provide disease control, other benefi cial effects of applying such agents have been observed. For example, liquid formulations of both hydrophobic and hydrophilic particle fi lms were shown to double yields of pear in fi eld trials, while delayed fruit maturation, increased fruit size, increased fruit number and increased fruit yield were obtained following use of kaolin particle fi lms (Lalancette et al, 2005). In the latter case, the authors attributed the effects to a reduction in plant stress.…”

“…on apple leaves, although it was not consistently effective against the cedar apple rust pathogen Gymnosporangium juniperi-virginianae (Thomas et al, 2004). In a recent four-year study, hydrophobic kaolin particle fi lms failed to control Cladosporium carpophilum or Podosphaera leucotricha on peach, although it did control Monilinia fructicola (Lalancette et al, 2005). In contrast, hydrophilic kaolin particle fi lms did not control any of the peach pathogens, leading the authors to suggest that hydrophobicity and deposit density may be important factors for effective disease management (Lalancette et al, 2005).…”

“…In a recent four-year study, hydrophobic kaolin particle fi lms failed to control Cladosporium carpophilum or Podosphaera leucotricha on peach, although it did control Monilinia fructicola (Lalancette et al, 2005). In contrast, hydrophilic kaolin particle fi lms did not control any of the peach pathogens, leading the authors to suggest that hydrophobicity and deposit density may be important factors for effective disease management (Lalancette et al, 2005). Whether or not kaolin particle fi lms provide disease control, other benefi cial effects of applying such agents have been observed.…”

Japanese Beetle and Other Coleoptera Feeding on Grapevines in Eastern North America

“…Ladd et al ( 1978 ) showed that extracts of neem seeds were highly repellent to adult JB, protecting sassafras and soybean leaves almost completely from JB feeding. Some commercial formulations of azadirachtin also performed well against adults on peach (Lalancette et al 2005 ) . In Florida, studies showed azadirachtin to cause low morbidity and mortality against adult JB (Vitullo and Sadof 2007a, b ) .…”

“…Particle fi lm technology such as kaolin successfully reduced JB adults and their damage in peach (Lalancette et al 2005 ) . A disadvantage of this product is the high use rate recommended, i.e.…”