Budworm Control on Sweet Corn, Spring, 1982

Abstract

Abstract ‘Goldcup’ sweet corn was planted 26 May in Myakka fine sand on the Univ. of Florida Agric. Res. and Educ. Cent, in Sanford. Nemacur 15G 2 lb (AI)/acre was incorporated at planting time in a 15 in band for nematode control. A plot consisted of two 20-ft rows with 30 in-row spacing and 12 in-plant spacing. Plots were separated by 60 in (two row spacings). Treatments were replicated in four randomized complete blocks separated by 10 ft. weed-free alleys. Sprays were applied with a CO2 pressurized sprayer mounted on an Allis-Chalmers model G tractor. Three nozzles (D3-45) were used per row; one overhead and one drop on each side. The delivery rate was 50 gal/acre with a boom pressure of about 50 lb/in2 and a speed of 3 mph. Baits were broadcasted over-the-top in premeasured amounts wiith a shaker-can. Lannate 1.8L at .45 lb (AI)/acre was applied to the entire experiment (including untreated check) on 11 June, due to a severe infestation of fall armyworm, Spodoptera fruqiperda (J. E. Smith), that threatened the existence of the experiment. Baits were applied 15 and 22 June. Sprays were applied 16 (except Pounce) and 22 June. The effectiveness of the treatments applied on 15 and 16 June is questionable, due to 0.85, 0.24, and 4.0 in of rain on 15, 16, and 17 June, respectively. Applications made on 22 June were not as severely affected by rain; 0.1 and 0.2 in on 23 and 24 June. Damage ratings were taken when the plants were 12 to 18 in tall; the stage considered most susceptible to bud destruction by fall armyworm. Twenty plants (10 in each row) per plot were rated for damage on 25 June as follows: 1, no damage; 2, etching only (evidence of foliar feeding by newly hatched larvae); 3, damage to bud; and 4, bud completely destroyed. Twenty plants (10 in each row) per plot were rated for damage on 28 June as follows: 0, no damage; 1, etching only; 2, light bud damage; 3, severe bud damage; and 4, bud completely destroyed.