The adults of several species of stink bugs and plant bugs suck the sap
from young pecan nuts causing an injury known as black pit, in which the
interior of the nuts turns black. The injured nuts fall from the trees
before the shells harden.
Feeding by the insects after shell hardening, Figure 14, produces brown
or black spots on the kernels. Areas affected taste bitter, but the
remainder of the kernel is unaffected.
Stink bugs are familiar to everyone. Plant bugs resemble them and are
usually shades of brown, smaller and narrower in body outline.
Plant bugs and stink bugs overwinter in the adult stage in debris on the
ground. In the spring, the adults are attracted to growing vegetation
such as cover crops or weeds, where they deposit their eggs. The
immature bugs develop on low-growing vegetation. When they reach
maturity, their wings are fully developed and they fly to pecan trees. A
few eggs may be deposited on pecan trees, but the young bugs apparently
are unable to develop on them. Only the adults are present in sufficient
number to inflict economic injury. There may be as many as four
generations each year.
_Control._—Although certain insecticides will control these pests, the
number and frequency of spray applications necessary for control would
not be economical.
Care should be taken to keep weeds down in the orchard during the
growing season. Winter cover crops should be plowed down early in the
spring so they will not be attractive to the adults coming out of
hibernation. If this operation is delayed, the bugs will leave the cover
crop when it is removed and migrate to the trees in large numbers.