DBM ON HEAD CABBAGE MANAGEMENT WITH INSECTICIDES, 1996:

R. F. L. Mau and L. R. Gusukuma-Minuto
University of Hawaii
Dept. of Entomology
3050 Maile Way, Rm. 310
Honolulu, HI 96822
Phone: (808) 956-7063
 
R. S. Shimabuku
Cooperative Extension Service
310 Kaahumanu Ave., Bldg. 214
Kahului, HI 96732

 

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
___(1 July)___

     

6 DAT 2
_____(15 July)______

         

6 DAT 4
______(29 July)______

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
____(12 August)_____

         

Harvest
_____(19 August)_____

         

Seasonal means +
______SEM______

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