Utilization of entomopathogenic fungi as biological control

Source PCARRD Highlights 2008. Pp. 92-93
Classification Information for dissemination
Title Utilization of entomopathogenic fungi as biological
control agents against major insect pests of
Researchers Golez, H.G.; Bignayan, H.G.; Flor, R.B.; Macahilo,
Agency National Mango Research and Development
Source of
Mango ‘Carabao’ ranks third next to banana and pineapple as top fruit export of the Philippines. An estimated 2.5 million farmers are directly or indirectly dependent on the mango industry. However, yield of mango in the Philippines is relatively low as compared to other mango producing countries. This low yield is usually attributed to the occurrence of insect pest and diseases. Fruit flies (Bactrocera philippinensis and Bactrocera occipitalis) and mango leafhopper (Idioscopus clypealis) are the common mango insect pests in the
Philippines. While these insect pests are commonly controlled with chemical pesticides, indiscriminate use has resulted in the development of insect resistance. Hence, Golez et al. (BPI-NMRDC) studied entomopathogenic fungi as an alternative biological control agents against major mango insect pests.
1.   Two fungal species, Hirsutella versicolor from mango leafhopper and Verticillium sp. from June beetle were recovered as a result of survey and collection of entomopathogenic fungi conducted in the provinces of Guimaras, Iloilo, and Negros Occidental. Isolates of other entomopathogenic fungi were obtained from different sources including Sporothrix insectorum, Aphanocladium album from the Insect Pathology Research Center, Boyce Thompson Institute, New York (ARSEF); Metarhizium anisopliae (ARSEF, Leyte State University) and RCPC Cebu; and Beauveria bassiana and Verticillium lecanii (ARSEF and Leyte).

2.   In general, rice either whole or broken in combination with water promoted conidial growth of the entomopathogenic fungi.

3. Beauveria bassiana at 1 x 108 and 1 x 1010 conidial/ml resulted in 100% mortality of mirid bugs at 2–4 days after treatment.

4.   Mortality and mycosis of fruit flies differed significantly based on conidial concentrations of the four entomopathogenic fungi. Beauveria bassiana and Metarhizium anisopliae at 1 x 108 and 1 x 109 conidial/ml resulted in the highest mycosis that ranged
from 82% to 93% on Bactrocera philippinensis, and 88%–92% on Bactrocera occipitalis. Verticillium lecanii at 1 x 109 conidial/ml resulted in 57% and 68% mycosis on Bactrocera
philippinensis and Bactrocera occipitalis, respectively.

5.   Mango leafhoppers treated with Beauveria bassiana and Metarhizium anisopliae obtained a cumulative mortality of 56.50% and 42.83%, respectively.

Entomopathogenic fungi have the capability to control insect pest of mango under laboratory condition. However, further studies are necessary to improve its effectiveness under field condition. Low-cost materials like rice, corn, water, and coconut milk could be
used for the mass production of the entomopathogenic fungi. Moreover, its integration with other insect control strategies may reduce the excessive reliance on chemical pesticides.