Feb 21, 2018 - beds 32 inches wide and 240 ft long were fumigated with methyl bromide/chloropicrin 67/33 at a rate of .220 lbs/acre, fertilized with a bottom ...
Arthropod Management Tests, Vol. 22
E: VEGETABLE CROPS
CABBAGE: Brassia oleracea capitata L. 'Solid Blue' Diamondback moth (DBM) Plutella xylostella (L.)
P. A. Stansly & J. M. Conner University of Florida/FAS SW Florida Res. & Ed. Ctr. Immokalee, FL 33934 (941)675-7235
111
(3 IE)
CONTROL OF DIAMONDBACK MOTH (DBM) WITH EMAMECTIN AND BACILLUS THURINGIENSIS ENDOTOXINS, 1996: Six beds 32 inches wide and 240 ft long were fumigated with methyl bromide/chloropicrin 67/33 at a rate of .220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre 5-16-8 and a top mix of 500 lbs/acre of 19-0-19, and covered with black polyethylene film. The center bed of each of 2 sets of 3 beds on 6-ft centers separated by a 15 ft drive middle was planted on 5 Dec 1995 with collard seedlings var 'Georgia' to provide target pest inoculum. Cabbage seedlings were transplanted 29 Jan into single rows on the remaining 4 beds at 18 inch spacing. Beds were subsurface irrigated with a semi-closed system and plants sprayed with Bravo 720 at 1.5 pt/acre for disease control. Each bed of cabbage was considered a block and divided into 7 plots 34 ft long in a RCB design with 4 replications and 7 treatments. A precount on 1 April of 20 plants per replication yielded an average 1 DBM larva and 0.8 DMB pupa per plant. Treatments were applied on 2, 11, and 17 Apr at a rate of 65 gpa using a high clearance sprayer equipped with 5 yellow hollow cone Albuz ceramic nozzles per row and operating at 200 psi of pressure. A nonionic surfactant, ASPA 80, was tank mixed at the rate of 16 oz/100 gal of spray which was made up with water at pH 7.2. Proclaim was not applied on 11 Apr at the request of the company representative. Ten randomly selected plants per plot were evaluated weekly 4 to 7 DAT. Five wrapper leaves and 3 inner (head) leaves per plant were inspected for larvae classified in 3 size categories. A damage rating was determined for each plant where 1 = no apparent damage, 2 = 0-1 % surface area damage to wrappers, 3 = 2 - 5 % damage to wrappers but none to head, 4 = 6-10% damage to wrappers, 0 - 5 % damage to head, 5 = 11-30% damage to wrappers, 5-15 damage to head 6 = > 3 0 % damage to wrappers, 15% damage to head. Evaluations were recorded on Pesticide Research Manager version 4.06. The 15 largest heads in each plot were selected and graded for marketability on 25 Apr based on 2 levels of stringency: "Fancy" with no insect damage on the wrapper leaves or head, and "Standard" with less than 10% insect damage on wrapper leaves and less than 5% on the head, limited to the 2 outer leaves. A heavy infestation of DBM built up first in the inoculum rows of collards and migrated into the cabbage plots, especially toward the end of the trial. There were no significant differences in number of DBM larvae on 9 Apr but on 15 Apr, fewest larvae were seen on plants treated with Crymax, Mattch, Cry-IF and CRY-1C. Damage ratings were lowest for Mattch-treated plants. On 22 April, all Bt treatments had fewer larvae than Proclaim which had not been sprayed the previous week but still had fewer than the untreated check. Damage ratings were again lowest on plants treated with Mattch. Over all dates, larvae were fewest on Mattach-, Crymax- and Xentari-treated plants, although not significantly less than CRY-1C. Least damage was seen on plants treated with Mattch or Xentari, though not significantly less than the Crymax treatment. The highest number and weight of Fancy heads was harvested from plants receiving Mattch, although the weight of Fancy heads produced by Crymax-treated plants was not significantly different. The largest number of marketable heads (Fancy + Standard) was produced by plants sprayed with Xentari, Mattch or Crymax, although not significantly more than with CRY-1C. The same treatments produced the highest weight of marketable heads with the addition of Proclaim. In summary, all treatments provided significant protection against DBM, but no treatment provided complete protection. Mattch, followed by Crymax, appeared to perform best over all criteria, with Xentari and CRY-1C next in order. Proclaim-treated plants suffered from the missed application when pressure from DBM was most intense. MEAN NO. DBM LARVAE AND DAMAGE RATING FOR 10 PLANTS BY SAMPLE DATE. Apr. 9 Treatment/formulation Cry-IF Cry-lC Mattch Proclaim . 16E CRYMAX WDG Untreated Check Xentari
Rate/acre 2.6 qt 2.2 qt 2.0 qt 0.0075 lb(AI) 1.0 1b 0.5 1b
Apr. 15
Apr. 22
Average
DBM
Damage
DBM
Damage
DBM
Damage
DBM
Damage
0.45 1.35 L92 2.65 0.60 0.78 8.50
2.92cd 3.22bc 3.40b 3.60ab 2.75d 2.83d 3.92a
0.55d 3.55b 1.05d 2.02c 0.42d 0.60d 7.60a
2.83de 3.47b 3.17bc 3.30b 2.55e 2.90cd 4.72a
0.40c 2.50b 0.33c 1.02c 0.05c 0.82c 7.83a
3.22cd 3.67b 3.42bc 3.65b 2.72e 3.02de 4.85a
0.47d 2.47b 1.10c 1.90b 0.36d 0.73d 7.97a
2.99cd 3.46b 3.33bc 3.52b 2.67d 2.92d 4.50a
Means in the same column followed by the same letter are not significantly different (P < 0.05, Fisher's protected LSD) MEAN NO. AND WEIGHT (LB.) OF FANCY, AND STANDARD CABBAGE HEADS, TOTAL MARKETABLE AND NON-MARKETABLE HEADS OF THE 15 LARGEST HEADS PER PLOT Marketable Heads Non-Marketable Heads Fancy formulation Cry-IF 1 Cry-lC • Mattch i Proclaim . 16E i CRYMAX WDG Xentari 1 Untreated Check
Standard
Total
amt/acre
No.
Lb.
No.
Lb.
No.
2.6 qt 2.2 qt 2.0qt 0.0075 lb (AI) 1.01b 0.5 1b
5.50b 0.75d 3.25bc 1.50cd 8.25a 0.25d 43.25bc
35.25a 4.08cd 19.15bc 9.95bcd 45.85a 1.25d 19.57b
8.50a 9.50a 9.00a 8.75a 5.75b 1.50c 10.00a
47.70ab 59.35a 57.18a 44.48ab 35.95b 7.45c 57.95a
14.00a 10.25b 12.25ab 10.25b 14.00a 1.75c 13.24a
Lb. 82.95a 63.43ab 76.32ab 54.43b 81.80a 8.70c 77.53ab
Means in the same column followed by the same letter are not significantly different (P < 0.05, Fisher's protected LSD)
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No.
Lb.
1.00c 4.75b 2.75bc 4.75b 1.00c 13.25a 1.75c
7.18c 28.98b 17.70bc 25.12b 5.87c 74.37a 10.50c
