ARS | Publication request: Nezara viridula feeding patterns in macadamia nut in Hawaii; nut maturity and cultivar effects

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 2009
Publication Date: September 1, 2009
Citation: Follett, P.A. 2009. Nezara viridula feeding patterns in macadamia nut in Hawaii; nut maturity and cultivar effects. Environmental Entomology. 38: 1168-1173.

Interpretive Summary: Macadamia nut (Macadamia integrifolia, Proteaceae) is the largest orchard crop grown in Hawaii with 18,000 arces in production and a total farm value of $30-40 million (HASS 2005). Nezara viridula L. (Hemiptera: Pentatomidae) is one of the main insects pests of macadamia nuts. Studies were conducted to determine cultivar susceptibility throughout the growing season in nuts of varying maturity classes using ruthenium red dye to stain stink bug probes. Damage occurred in the tree and on the ground during all nut growth stages. Damage on the ground was often higher than in the tree. This suggest nuts are damage in the tree and then after nuts fall to the ground additional damage occurs. Cultivar 246 was more susceptible to attack than cultivars 333 and 800. It was previously thought that cultivar susceptibilty was related to husk and shell thickness, but cultivar 246 showed higher damage that other cultivars even during early nut development when the nuts are small and before the shell has formed. This suggest that shell and husk thickness may play a secondary role in susceptibility to feeding by N. viridula. Monitoring Nezara viridula feeding activity during early nut development may help alert growers to potential problems later in the season, but early season probing activity in immature nuts was not a good predictor of damage levels in mature nuts later in the season in our study.

Technical Abstract: Nezara viridula L. is a serious pest of macadamia nuts, Macadamia intergrifolia, in Hawaii. Using ruthenium red dye to stain stink bug feeding probes, feeding activity was determined for nuts of various maturity levels harvested from the tree and off the ground throughout the growing season in six commercial cultivars. Damage occurred in the tree and on the ground during all nut growth stages. Damage on the ground was often higher than in the tree. This suggest nuts are damaged in the tree and then after nuts fall to the ground additional damage occurs. Cultivar 246 was more susceptible to attack than cultivars 333 and 800. It was previously thought that cultivar susceptibility was related to husk and shell thickness, but cultivar 246 showed higher damage than other cultivars even during early nut development when the nuts are small and before the shell has formed. This suggests that shell and husk thickness may play a secondary role in susceptibility to feeding by N. viridula. Monitoring Nezara viridula feeding activity during early nut development may help alert growers to potential problems later in the season, but early season probing activity in immature nuts was not a good predictor of damage levels in mature nuts later in the season in our study.