Citrus Thrips (Scirtothrips citri), an Emerging Pest of Mid to Late Season Cotton in the Low Desert

Citrus thrips (Scirtothrips citri) has been increasing during the past decade as a low desert cotton pest during the second half of the growing season, appearing from July-October.  Thrips numbers and associated feeding damage necessitating insecticide applications to many local fields in 2018.  Cotton on field borders is colonized and damaged first, with populatons building before dispersing across the field.  Youngest/tneder leaves are first damaged by citrus thrips feeding, resulting in bronzed leaves before they dessicate and abscise when there is severe feeding injury. Severe damage by citrus thrips feeding also results in curled leaf tips and bracts. Boll losses have been noted, but yield losses not yet quantified. Insecticide trial efficacy data from 2018 did not note any insecticides providing adequate control.  Depictions of damaged cotton plants and fields will also be presented.