Potential vs Mango Fungal Disease: 2 microorganisms tested as 'biocontrol agents'

MANILA, Philippines - Researchers from the Mariano Marcos State University (MMSU) in Batac City, Ilocos Norte have discovered the potential of two microorganisms commonly found in soil as “biocontrol agents” against Colletotrichum gloeosporioides, the most serious fungal disease of mango.

Colletotrichum gloeosporioides, a causal organism of anthracnose, is the most serious fungal disease in mango, according to the Department of Science and Technology’s Philippine Council for Agriculture, Forestry and Natural Resources Research and Development.

Dr. Thelma Layaoen, MMSU professor and study leader, said the microorganisms — Trichoderma harzianum and Bacillus subtilis — were able to control and reduce the infection caused by anthracnose.

In the Philippines, anthracnose and stem-end rot are considered the most serious and destructive diseases of mango.

Anthracnose infects almost all mango parts, including floral panicles, twigs, leaves, and fruits of mature and immature trees, PCARRD said.

On the other hand, stem-end rot is considered a major problem limiting the storage and shelf life of mangoes, it said.

“To test the fungicidal effect of the microorganisms, suspensions of pure cultures were sprayed on anthracnose-infected mango seedlings every two weeks,” Layaoen said.

She said the fungicidal effect of the microorganisms, 12 to 14 weeks after treatment, is comparable with the use of commercial fungicide and could be used as an alternative.

The researcher also recommended that the technology could be part of an integrated pest management program for mango to reduce the use of chemical pesticides.

The result of the cost analysis study, however, showed that the use of the microorganisms as biocontrol agents is 20 percent more expensive than commercial fungicide.

“Hence, it is recommended that low-cost materials for the production or multiplication of the microorganisms be studied further to reduce the cost,” Layaoen said.

PCARRD said the MMSU researchers also noted that the microorganisms are sensitive to heat, so they recommended that application be done in the late afternoon.

“The researchers see potential for these biocontrol agents and stress the long-term beneficial effect of the microorganisms on the environment and human health,” PCARRD said.

The United Nations’ Food and Agriculture Organization (FAO) said the Philippine mango industry supports nearly 2.5 million farmers nationwide.

Mango is the third ranking Philippines fruit export next to bananas and pineapples, with exports going predominantly to Japan, Singapore and Hong Kong.

The Philippines ranks seventh as a global mango exporter, well behind India, which exports more than half of the world’s mangoes, FAO said.