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Control of Southern Armyworm & Beet Armyworm on Staked Tomato Biopesticides & a Pyrethoid, 1999
P. A. Stansly, J. M. Conner and D.R. Peach
University of Florida/IFAS
Southwest Florida Res. and Ed. Center
2686 State Road 29 North
Immokalee, Florida 34142-9515
Phone: (239) 658-3427
Fax: (239) 658-3470
Email: pas@ifas.ufl.edu
TOMATO: Lycopersicon esculentum Mill. ‘Solar Set’
Southern Armyworm Spodoptera eridania (Cramer)
Beet Armyworm Spodoptera exigua (Hübner)
Southern armyworm is the worst noctuid pest of tomatoes in southwest Florida and beet armyworm is occasional. This study evaluated the efficacy of 3 biopesticides and broad-spectrum pyrethroid toward the goal of providing growers with comparisons of different control options for these pests. Greenhouse-raised seedlings were planted 30 Sep at 18-inch spacing on 2 sets of 3 beds which had been provided with 800 lbs/acre of 5-16-8 dry fertilizer, fumigated with a 67/33% mixture of methyl bromide/chloropicrin at a rate of 300 lbs/acre and covered with white face polyethylene film. An additional 175 N and K /acre were fertigated through NetafimÔ drip tape with 12 inch emitter spacing during the growing season. Plants were staked and tied according to
standard practices and sprayed with a combination of Maneb 80 WP at 1 lb/acre plus Kocide 101 at 3 lb/acre for disease control. The center bed in each set of 3 beds was left untreated to serve as a source of pest inoculum. The 4 treated beds were divided into plots 48 ft long to which 5 treatments were assigned in a completely randomized block design with 4 replications. Treatments were initiated after a mean of 1.8 armyworms per plant was observed on 15 plants per replicate 22 Nov. A high clearance sprayer was used, operated at 200 psi with two vertical booms, each fitted with ceramic "yellow" Albuz tm hollow cone nozzles delivering 66 gpa with 3 nozzles per boom 23 Nov and 88 gpa with 4 nozzles 29 Nov and 6, 14, 21 and 28 Dec for a total of 6 applications. The
adjuvant Latron B-1956® at 1 % v/v was added to all treatments. Six weekly evaluations were performed starting 29 Nov to monitor damage and larvae on 6 plants per plot. Damage was rated as 0 = no damage, 1 = 1% leaflets with damage, 2 = 2 to 5%, 3 = 6 to15%, 4 = 16 to 30% and 5 > 30%. Two harvests were made from 16 plants per plot on 28 Dec and 10 Jan. Fruit was evaluated for quality and size on a commercial grading table.
SAW predominated through the trial with BAW found only on untreated plants during the first evaluation. SAW numbers increased rapidly in the control plots during early Dec, peaking at a mean 18 per plant on 6 Dec, then decreasing to 3.2 by the first harvest in late Dec. Significant differences in number of larvae were seen between all sprayed treatments and the untreated control. Fewest larvae were observed on plants treated with Warrior but not significantly fewer than on Javelin-treated plants. There were significantly fewer larvae on plants treated with Javelin compared to Lepinox. Damage rating was lowest for plants treated with Warrior, again with significant differences between Javelin and Lepinox which wasn’t different from the control, in
contrast to celery looper NPV. Number and weight of extra-large and total fruit was greatest from plants sprayed with Warrior, followed by Javelin. There were no significant yield differences between the control and either celery looper NPV or Lepinox. Fewest insect-damaged culls were harvested from plants treated with Warrior. Thus, Javelin could provide a control option against SAW even though efficacy was not equivalent to that provided by Warrior.
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Mean larva counts, damage ratings, marketable and unmarketable fruit |
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Treatment/ Formulation |
Rate/acre |
Larvaea |
Damage Ratinga |
Marketable |
Unmarketable Insect |
|
X-large |
Totalb |
Total |
|
No |
Wt (lb) |
No |
Wt (lb) |
No |
Wt (lb) |
|
Javelin WG |
1.0 lb |
2.2c |
1.9c |
139.5b |
66.8b |
299.5b |
105.1b |
158.3a |
52.3a |
|
Lepinox WDG |
1.0 lb |
5.7b |
3.4ab |
65.5c |
30.3c |
140.5c |
48.0c |
152.5a |
45.6a |
|
Warrior T 1 CS |
0.025 lb ai |
0.1c |
0.6d |
334.0a |
1546a |
687.3a |
240.8a |
167.5b |
8.1b |
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Celery looper NPVc |
2 oz |
6.3b |
3.1b |
77.5bc |
36.7bc |
164.0c |
57.8c |
166.8a |
52.2a |
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Untreated |
|
13.4a |
3.8a |
57.0c |
28.3c |
96.0c |
37.4c |
167.5a |
45.3a |
Means in columns followed by the same letter are not significantly different (LSD, P<0.05)
aMean number over all dates of total larval and foliar damage per plant
bMean number includes X-large and all other marketable fruit from 16 plants for 2 harvests
cOcclusion bodies of Anagrapha falcifera multicapsid nuclear polyhedrosis virus (AfMNPV) |
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