Is Haplothrips clarisetis Priesner (Thysanoptera: Tubulifera) an Economic Threat to Table Grapes in the Lower Orange River Production Region of South Africa?

Table grape producers and consultants in the Lower Orange River region, Northern Cape province,have been reporting conspicuous, fairly large, black thrips on new growth and inflorescences early inthe growing season in recent years. These thrips were identified as Haplothrips clarisetis Priesner andH. nigricornis Bagnall, both indigenous species widely distributed in South Africa and Africa. The aimof this investigation was to determine if H. clarisetis causes any damage to table grapes and if it posesan economic threat to the industry in the Northern Cape province. Inspections were conducted overtwo seasons during flowering and fruit set, prior to and after harvest in four vineyards near Augrabies(28.7630 S, 20.5668 E) and four in the Blouputs Valley (28.4631 S, 20.0789 E) where Haplothrips hadpreviously been reported. Developing inflorescences, bunches, leaves and shoot tips were inspected for thepresence of Haplothrips and for any signs of feeding damage. Very few thrips were found and no signs offeeding were observed. Adult H. clarisetis were collected from flowering grape bunches and from flowersof Osteospermum microcarpum (Asteraceae) and Mesembryanthemum crystallinum (Aizoaceae) growingwild adjacent to the vineyards and confined on grapevine flowering bunches, leaves and a single shoot tip.Daily inspections showed no signs of feeding damage on the shoot tip, leaves or inflorescences and thripsdid not survive for more than three days on average. We therefore conclude that H. clarisetis does not posean economic threat to table grapes in the Lower Orange River region.