EFFECTS OF IMIDACLOPRID ON COLONIZATION OF APHIDS AND SILVERLEAF WHITEFLY AND GROWTH, YIELD AND PHYTOTOXICITY IN CAULIFLOWER

Imidacloprid transplant drench root plug treatments of cauliflower and imidacloprid treatments preplant in-furrow soil injections were evalu ated for their effects on colonization of silverleaf whitefly, Bemisia argentifolii Bellows & Perring, green peach aphid, Myzus persicae (Su lzer), and cabbage aphid, Brevicoryne brassicae (Linnaeus). Whitefly t reatments included imidacloprid root plug treatments of 180, 270, and 360 g AI/ha, an in-furrow treatment of 360 g AI/ha, and an untreated c ontrol. Aphid treatments included imidacloprid root plug treatments of 90, 180, and 270 g AI/ha, an in-furrow treatment of 360 g AI/ha, and an untreated control. The untreated control plants had significantly g reater numbers of apterous aphids and whitefly nymphs than imidaclopri d treatments. The imidacloprid in-furrow treatment had significantly f ewer whitefly immatures than other treatments on several sampling date s. Phytotoxicity evaluations revealed some leaf tissue necrosis from r oot plug treatments of imidacloprid during the fall planting. Plant gr owth was retarded, harvest was delayed, and yield of kg of marketable heads was lower for the untreated control cauliflower plants due to hi gher whitefly infestation. Reduced yields due to aphids was not observ ed in the fall planting.