Lygus bug and its management in strawberries Lygus bugs (Lygus spp.) • Manage weeds in winter. Once adults emerge, are important pests of they will migrate to strawberries when weeds strawberries in Central senesce or are removed. Mow or disc weeds or Coast and Oxnard. Their alternative hosts while Lygus is in nymphal stage. feeding causes significant reduction in the yield and • Growing flowering hosts near strawberry plants to quality of the fruit. Lygus attract lygus and managing them is one approach infestation is more severe and requires careful management. when fruit is continuously present in the fields. • Vacuuming from trap crops or strawberries can reduce lygus numbers, but it can also remove Biology: Depending on the beneficial arthropods. temperature, egg period, early nymphal (1-3 instars) • Biological control includes naturally occurring and late nymphal (4-5 instars) stages can each last predators like big-eyed bugs (Geocoris spp.), for about 7 days. Adults may take up to 9 days damsel bugs (Nabis spp.), minute pirate bug before they start laying eggs and egg laying can (Orius tristicolor) and several species of spiders. continue for 21 days. On strawberries, majority of the Commercially available egg parasitoid, a wasp eggs are laid in inflorescence compared to leaves. (Anaphes iole) that attacks lygus eggs can Eggs are inserted into the plant tissue. Newly reduce populations, but not below threshold emerged nymphs are levels. small and pale colored and can be confused • Use the available insecticides judiciously. Rotate with aphids, but they different chemicals to reduce the risk of move fast compared to insecticidal resistance. Note that insect growth aphids. Older nymphs regulators work by disrupting the insect can be recognized by development while other chemicals can cause five black spots (four immediate mortality depending on the mode of on the thorax and one action. in the middle of the abdomen) on their back. Additional information: Damage: Several flowering weeds and legumes like alfalfa are preferred hosts of lygus compared to • For a quick reference about lygus bug and its strawberries. However, management, check UC IPM website at: infestations in http://www.ipm.ucdavis.edu/PMG/r734300111.ht strawberries can cause ml significant damage. Feeding, by puncturing • UC ANR manual, “Integrated pest management and sucking plant juices, for strawberries” (Publication number 3351) has will damage developing detailed information about strawberry production achenes (seeds) and and various management practices. result in fruit deformation. Damage is severe during • Field key to identify common species of Lygus flowering. can be found at: http://lygus.uckac.edu/PDF/ANR%208104.pdf Sampling: Divide field into four blocks and sample four 200-foot lengths of row in each block. Sample 10 plants/200-foot row by beating the plant to collect _________________________________________ lygus into a tray placed under the plant. Treatment Surendra Dara threshold is one lygus nymph per 20 plants. If a bug- Strawberry and Vegetable Crops Advisor vac is used to sample, the threshold is one lygus per UC Cooperative Extension 10 plants. 624A West Foster Rd, Santa Maria, CA 93455 Phone: 805-934-6240 Fax: 805-934-6333 Management options: Web: cesantabarbara.ucdavis.edu www.twitter.com/calstrawberries www.twitter.com/calveggies • Thorough and regular monitoring is important to ___________________________________________________ make treatment decisions. .