RESPONSE OF COTTON PLANTS TO ALDICARB SOI L APPLICATION

The insecticidal activity of aldicarb (Temik(R)) (2-methyl-2-(methylth io) propionaldehyde-0-(methylcarbamoyl) oxime) has been extensively do cumented but less is known regarding its effect on cotton (Gossypium h irsutum L.) plant growth. Aldicarb was applied to field grown cotton a t 2.02 and 2.52kg (ai)/ha in 1990 and 1991, respecively, at squaring t o first flower stages of plant growth. Lateral root length density was determined in increments of 20 cm, to a depth of 80 cm from the soil surface in 1990 and 40 cm in 1991. Tap roots were sampled in 1991. Ald icarb-treated plants had larger lateral root systems than untreated pl ants at soil depths of 0-20 cm from the soil surface on the cotton bed . Tap root weight was also higher in aldicarb-treated plants compared to untreated cotton. Aldicarb increased lint yields 73% in 1990 and 31 % in 1991 compared to untreated plants. Cotton plant leaf temperatures , transpiration, leaf water potentials, leaf area indices, and photosy nthesis measurements were significantly correlated to increased cotton plant root growth in plants treated with aldicarb.