Submitted to: Southeastern Pecan Growers Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 28, 1997
Publication Date: N/A
Interpretive Summary: Stink bugs and leaf-footed bugs migrate into pecan orchards throughout the growing season, particularly during Aug-Nov, piercing through the pecan shell and feeding upon the kernel. This causes the nut to fall from the tree or black, circular lesions to form on the kernel surface, resulting in an unmarketable bitter tasting kernel. Insecticides used to control these pests kill beneficial insects which control pecan aphids, are illegal to spray after the shuck (husk) splits open, and pose health and environmental risks. Results showed that stink bugs prefer Desirable over Stuart pecans. The results suggest that pecan growers' may effectively interreupt migrating stink bugs from entering the orchard, and reduce their feeding damage in trees adjoining soybeans, by planting a strip of speckled purple hull pea along the border of the orchard. Stink bugs are concentrated and then controlled with insecticides within the peas (resulting in reduced insecticide use). This technique may be used through to pecan harvesst (during the time when insecticide use within the orchard trees is illegal). Verification of these results is in progress, and should be completed prior to adoption of this insect pest management strategy by growers.
Technical Abstract: Stink Bug and leaf-footed species, migrate into pecan orchards during the growing season, particularly from soybean senescence to harvest. These pests pierce through the shell and feed upon the kernel, and cause black pit' (kernel turns black and the fruit falls from the tree), as well as kernel spot' (localized, black, circular lesions on the kernel surface resulting in an unmarketable bitter kernel). Current control tactics are largely based upon the utilization of insecticides. However, insecticides are restricted during the three to four weeks prior to pecan harvest, are difficult to apply in a timely manner, and often result in increased late season aphid problems. Therefore, trap cropping, where other plants are grown in order to attract insects away from the target crop, was investigated. Results showed that speckled purple hull pea is a suitable trap crop plant based upon attractiveness to stink bugs, which results from mpea pod production during the primary stink bug migration out of soybeans. This pea variety also continues to produce attractive pods through pecan harvest. Results showed that stink bugs prefer Desirable pecan over Stuart pecan. The results also show that growers can use a drop cloth to check for stink bugs in a trap crop, which is needed to time the application of insecticides for stink bug control within the trap crop (resulting in reduced insecticide use and prevention of stink bug migration into the pecan orchard). Finally, results showed that when speckled purple hull pea is planted in a strip along the border of the orchard, it may effectively reduce stink bug feeding damage in trees adjoining the trap crop area of the orchard. Verification of these results is in progress, and should be completed prior to adoption of this IPM strategy.