THRIPS CONTROL ON BANANA USING THE BUNCH INJECTION METHOD, 1998:

R. F. L. Mau and L. R. Gusukuma-Minuto
University of Hawaii CTAHR
Dept. of Entomology
3050 Maile Way, Rm. 310
Honolulu, HI 96822
Phone: (808) 956-7063
FAX: (808) 956-5888
e-mail: maur@avax.ctahr.hawaii.edu
 
L. Okayama
Aloha Farms, Inc.
Aiea, HI 96701

 

BANANA: Musa cavendishii

‘Williams Hybrid’

Hawaiian flower thrips (HFT);

Thrips hawaiiensis

Adult and nymph HFT infest and damage developing banana fruits during the immature inflorescence stage. Each inflorescence is covered by purplish-red scales and is composed of a succession of overlapping bracts that contain the flowers. Adults enter the pod-like inflorescence as soon as it emerges from the pseudostem and oviposit into the immature flowers. Adults and larvae feed on petals, developing fruit and the interior surface of the scales. Extensive feeding on the immature fruit results in corky, scab-like adhesions. Plant reaction to oviposition punctures results in permanent raised, pimple-like bumps. Extensive occurrence of either types of damage affects fruit marketability. Growers in other banana producing countries prevent flower thrips damage by making a single insecticide application into the pod-like inflorescence within 3-4 days after it appears.

Diazinon is the only insecticide registered for use in controlling thrips and the banana aphid in Hawaii. Several insecticides were tested for HFT control. Ten insecticide treatments were tested in collaboration with Aloha Farms, Inc. The test field was located at Mokuleia, Oahu, HI. Treatments were arranged in a completely randomized design with ten replications per treatment. Each tree was a single plant treatment replication. Treatment was accomplished by injecting 50 ml of spray mix into tip of the inflorescence using a compressed gas sprayer set at 30 psi. Post treatment observations were made at 15 DAT and at harvest (ca. 102 DAT). For the first observation, ten fingers from alternate hands were sampled from each bunch where the hand at the top of the bunch was counted as "Hand 1". The number of oviposition pimples was counted and recorded. At harvest an overall bunch damage rating, based on the severity and distribution of the pimples, was assigned ("0" = no damage, increasing as the number and distribution of the pimples increased to a maximum rating of "5").

Developing inflorescence treated with Provado produced banana fingers with the least amount of HFT oviposition damage. Success and Diazinon provided moderate control. Alert and AgriMek did not provide adequate protection.

 

                                                            Mean no. pimple damage/hand at 15 DAT 1
Treatment/formulation     Rate lb
(AI)/50 gal
    Hand 1     Hand 3     Hand 5     Hand 7
AgriMek 0.15 EC     0.009     55.80b     50.28ab     59.69abc     55.00bc
AgriMek 0.15 EC     0.02     47.95b     48.52ab     56.76bc     74.81ab
Alert 2 EC     0.20     28.25cde     25.58cd     34.83de     26.46d
Alert 2 SC     0.30     40.73bc     47.29b     76.85ab     89.55ab
Diazinon 4 EC     0.50     47.11bc     33.84bc     49.20cd     64.43bc
Diazinon 4 EC     1.0     29.90de     27.49cd     37.13de     30.05d
Provado 1.6 F     1.0     21.43e     14.66d     16.42f     5.22e
Success     0.06     42.43bcd     22.95cd     23.00ef     54.86cd
Success     0.10     24.11e     38.85bc     35.00de     27.00d
Untreated check     ---     96.01a     72.10a     85.30a     106.40a

Means in the same column followed by a different letter are significantly different (Tukey’s studentized range test; P<0.01); SAS for Windows version 6.12.

 

 

Treatment/formulation     Rate lb
(AI)/50 gal
        Overall bunch damage
rating
1 at harvest
AgriMek 0.15 EC     0.009         3.22a
AgriMek 0.15 EC     0.02         3.07a
Alert 2 EC     0.20         2.38ab
Alert 2 SC     0.30         2.56a
Diazinon 4 EC     0.50         3.50a
Diazinon 4 EC     1.0         2.80a
Provado 1.6 F     1.0         0.95b
Success     0.06         2.38ab
Success     0.10         2.35ab
Untreated check     ---         3.50a
Means in the same column followed by a different letter are significantly different (Tukey’s studentized range test; P<0.01); SAS for Windows version 6.12.
1"0" = no damage, increasing as the number and distribution of the pimples increased to a maximum rating of "5".

 

 

 

Trade Composition\
Common name
    Formulation         name     Source
Agri-Mek     EC         abamectin     Merck & Co.
                       
Alert     SC         chlorfenpyr     American Cyanamid
                       
Diazinon     EC         diazinon     Prentiss
                       
Provado     F         imidacloprid     Bayer
                       
Success     SC         spinosad     Dow AgroSciences