DBM ON HEAD CABBAGE MANAGEMENT WITH INSECTICIDES, 1996:
HEAD CABBAGE: Brassica oleracea L. Tastie
Diamondback moth (DBM); Plutella xylostella (L.)
The insecticides were evaluated at the Kula Research Station, Maui Agricultural Park, from June to August. The field was set up in a randomized block design with six treatments and four replications (blocks). Each treatment plot consisted of a single row of cabbage planted at 18 in. between plant spacing. Treatments were applied using compressed carbon dioxide sprayer at 60 psi and 100 GPA. One hollow cone nozzle (TX-26) was used per row. The first treatment was applied one day after transplanting into the field on 2 Jul. Subsequently, six applications were made weekly until the week before harvest on the following dates: 8, 16, 23, 30 Jul, 6, 13 Aug.
A pre-treatment census for larvae was made the day before the first field spray application. Subsequent evaluations were conducted on a bi-weekly schedule for a total of five surveys. Ten plants were randomly selected from each treatment plot and carefully examined for larvae. For the pretreatment survey, 15 Jul and 12 Aug surveys, plants were assessed for larvae in the field. Plants were removed for the 29 Jul survey and at harvest.
No DBM larvae were observed in the field at the pre-treatment survey. Larval numbers in the check treatment first peaked at the cupping to early head formation stages of growth and again at harvest. All insecticides treatments provided good to excellent control of DBM larvae throughout the entire crop season. However, Proclaim 5 SG provided the best overall control; 97.5 % of the plants were marketable. Alert 2 SC and fipronil 80 WDG treatments also provided good to excellent control of the pest and resulted in acceptable marketability rates of 92.5 and 90%, respectively. The fipronil 1.67 SC and Mattch treatments were not as effective as the other treatments but significantly reduced DBM injury in comparison to that of the untreated check.
________________Mean number of DBM/10 plants_______________ |
Pre-treatment |
6 DAT 2 |
6 DAT 4 |
Treatment | Rate/Acre | Larvae | Pupae | Larvae | Pupae | Larvae | Pupae | |||||||||||||
Proclaim 5 SG | 0.0075 lb. (AI) | 0 | 0 | 0.00+0.00b | 0.00+0.00b | 0.00+0.00b | 0.00+0.00b | |||||||||||||
Alert 2 SC | 0.12 lb. (AI) | 0 | 0 | 0.00+0.00b | 0.00+0.00b | 0.00+0.00b | 0.00+0.00b | |||||||||||||
Fipronil 1.67 SC | 0.05 lb. (AI) | 0 | 0 | 0.00+0.00b | 0.00+0.00b | 0.03+0.03b | 0.05+0.22b | |||||||||||||
Fipronil 80 WDG | 0.05 lb. (AI) | 0 | 0 | 0.00+0.00b | 0.00+0.00b | 0.13+0.08b | 0.03+0.16b | |||||||||||||
Mattch | 2.0 qt. | 0 | 0 | 0.00+0.00b | 0.00+0.00b | 0.95+0.21a | 0.05+0.22b | |||||||||||||
Untreated check | --- | 0 | 0 | 0.58+0.12a | 0.08+0.27a | 0.98+0.19a | 0.25+0.54a |
Means in each column followed by a different letter are significantly different (Tukey's studentized range test P<0.001 SAS for Windows, version 6.11). Data was transformed by square root (X+0.5) prior to analysis. Untransformed means are presented.
________________________Mean + SEM of DBM_______________________ |
6 DAT 6 |
Harvest |
Seasonal means + |
Treatment | Rate/Acre | Larvae | Pupae | Larvae | Pupae | Larvae | Pupae | |||||||||||||
Proclaim 5 SG | 0.0075 lb. (AI) | 0.00+0.00b | 0.00+0.00a | 0.05+0.03c | 0.03+0.16b | 0.01+0.01c | 0.006+0.08b | |||||||||||||
Alert 2 SC | 0.12 lb. (AI) | 0.00+0.00b | 0.00+0.00a | 0.15+0.09c | 0.10+0.38b | 0.04+0.03c | 0.03+0.19b | |||||||||||||
Fipronil 1.67 SC | 0.05 lb. (AI) | 0.08+0.04b | 0.03+0.16a | 0.33+0.17bc | 0.13+0.33b | 0.11+0.04c | 0.04+0.21b | |||||||||||||
Fipronil 80 WDG | 0.05 lb. (AI) | 0.00+0.00b | 0.00+0.00a | 0.70+0.39bc | 0.03+0.16b | 0.21+0.10c | 0.01+0.11b | |||||||||||||
Mattch | 2.0 qt. | 0.00+0.00b | 0.00+0.00a | 1.38+0.40b | 0.30+0.91ab | 0.58+0.12b | 0.09+0.48b | |||||||||||||
Untreated check | --- | 0.30+0.08a | 0.05+0.22a | 4.48+0.99a | 0.98+2.83a | 1.57+0.29a | 0.34+1.49a |
Means in each column followed by a different letter are significantly different (Tukey's studentized range test P<0.001 SAS for Windows, version 6.11). Data was transformed by square root (X+0.5) prior to analysis. Untransformed means are presented.
Treatment | Rate/Acre | % Marketable heads | |||||
Proclaim 5 SG | 0.0075 lb. (AI) | 97.5+4.39a | |||||
Alert 2 SC | 0.12 lb. (AI) | 92.5+13.16ab | |||||
Fipronil 1.67 SC | 0.05 lb. (AI) | 85.0+11.32cd | |||||
Fipronil 80 WDG | 0.05 lb. (AI) | 90.0+12.40bc | |||||
Mattch | 2.0 qt. (AI) | 85.0+5.06d | |||||
Untreated check | --- | 20.0+18.9e |
Means in each column followed by a different letter are significantly different (Tukey's studentized range test P<0.0001 SAS for Windows, version 6.08). Percent marketable datum was transformed by arcsin prior to analysis. Untransformed means are presented.
Trade Composition\Common name | Formulation | name | Source | ||||||||
Alert | SC | pyrrole | American Cyanamid |
||||||||
fipronil | SC | fipronil | Rhone-Polenc | ||||||||
fipronil | WDG | fipronil | Rhone-Polenc | ||||||||
Mattch | ME | B. thuringiensis | Mycogen | ||||||||
Proclaim | WDG | emamectin benzoate | Merck |