Description of the Pest
False chinch bug is an occasional pest of young pomegranate. The adult is gray to light brown, elongate, and about 0.12 inch (3 mm). Females lay eggs on host plants or in cracks in the soil. The pale gray nymphs have reddish-brown abdomens. There are four to seven generations per year, with all stages present throughout the year.
False chinch bug nymphs spend the winter on weeds. During early spring, bugs primarily feed on foliage, stems, and seeds of cruciferous weeds. Important weeds that serve as hosts include wild mustard, wild radish, shepherd's-purse, and London rocket. When vegetation dries or is cut, bugs move to feed on virtually any nearby green plants, including irrigated fruit and nut trees, grains, and vegetable crops. The most serious infestations result from spring migrations; however, fall migrations can also occur. Adult bugs may swarm around trees in a manner superficially resembling leafhoppers.
Feeding damage is most severe in the spring as the trees start to leaf. Damage occurs when nymphs migrate from drying weeds or after mowing or plowing weeds. Migration may occur at any time for several days from April to October but are most common in May through July. Chinch bugs do not stay in one spot for very long and can spread out over an orchard within a week.
Large numbers of nymphs will stream over the dirt looking for any green vegetation. Heavy nymph infestations can kill sucker shoots in less than a day. This damage can occur within hours due to a toxin injected while feeding. The leaves dry up and are covered with fecal spots. Usually the nymphs do not climb higher than 1 to 2 feet on trees, so they pose little risk to mature trees. Young trees 1 to 2 years old may suffer severe damage.
Control weeds, especially in the first two years after planting pomegranates. Reducing bug numbers in weeds and neighboring agricultural fields prevents migration into orchards. Where possible, manage weedy areas such as ditches, pastures, and grasslands adjacent to orchards to prevent migration from these areas into pomegranate orchards. If heavy infestations of nymphs threaten young trees, treat immediately.
Disc under shepherd's-purse, London rocket stands, and other host weeds about 3 weeks before budbreak in young pomegranate trees. Waiting to disc after budbreak may result in heavy movement of bugs from the weeds to the trees. Creating a ditch filled with water between the migrating bugs and the orchard may prevent movement into the orchard.
Organically Acceptable Methods
Cultural control methods and applications of rosemary oil plus peppermint oil (Ecotrol) or pyrethrins may be effective.
Monitoring and Treatment Decisions
Visually inspect or use a sweep net to monitor weeds in fields or borders near young pomegranates for developing populations. False chinch bugs often hide under weeds at the soil line during the day. Visually inspect weeds by pulling them out of the ground, exposing the bugs to light. The false chinch bugs will begin to move around, making them easier to spot. In addition to weeds, inspect grow tubes or cartons used to protect young trees for false chinch bugs hiding inside. Be aware that populations will be moving around so you may need to monitor the entire orchard.
If possible, use cultural control methods or pesticides to manage false chinch bugs in weeds in and adjacent to the orchard before migrations occur. Pay special attention when weeds are drying or after mowing or discing. Treat for chinch bug in neighboring crops according to that crop's Pest Management Guidelines, to prevent migration into pomegranate. When nymphs are migrating into orchards, spraying them on the ground may be enough to prevent damage.
If a pesticide spray for young trees becomes necessary, methomyl (Lannate) is the most effective registered pesticide. However, methomyl disrupts natural enemies needed for other pests. Softer insecticides such as organic pyrethrins (PyGanic) have a very short residual and are less effective.
|Common name||Amount per acre||REI‡||PHI‡|
|(Example trade name)||(hours)||(days)|
|Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.|
|MODE-OF-ACTION GROUP NUMBER1: 1A|
|COMMENTS: Disruptive to natural enemies of mealybugs, caterpillars, soft scales, aphids, and other pests. Use of this pesticide may result in outbreaks of these pests. Methomyl is also toxic to bees and should not be applied when bees are actively foraging.|
|(PyGanic EC 1.4)#||2–4 pt||12||0|
|MODE-OF-ACTION GROUP NUMBER1: 3A|
|‡||Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.|
|*||Permit required from county agricultural commissioner for purchase or use.|
|1||Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers ("un"=unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee).|
|#||Acceptable for use on organically grown produce.|