Taitung Station Develops Fungus Strain to Combat Rice Pests in Organic Farming

Organic rice farmers in Taiwan's East Rift Valley region have long struggled with the rice plant bug (Leptocorisa chinensis), a pest that infests rice grains during the crucial heading stage. This infestation results in 'spot rice,' characterized by visible blemishes and a higher likelihood of grain breakage during milling, severely compromising quality. Previously, chemical pesticides were the only recourse, leaving organic farmers with few options to protect their crops.

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The rice plant bug often occurs during the heading stage of organic rice. This pest is widely distributed in Taiwan's plains and low to mid-altitude mountainous areas, with host plants mainly being rice and millet.

In response, the Taitung District Agricultural Research and Extension Station has successfully developed a biological control agent. Researchers identified a native strain of the white-muscardine fungus, Beauveria bassiana, from infected pest samples collected in the field. This strain, designated 'BB1031,' has shown remarkable efficacy in controlling the rice plant bug.

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After the transformation to organic cultivation in the second crop of 2023 in the rice fields of Guanshan Township, Taitung, severe pest infestations of the rice plant bug occurred in organic rice fields near mountains or primeval forests during the heading stage.

Field trials conducted over two cropping seasons in 2025 confirmed the effectiveness of the 'BB1031' strain. The fungus successfully infected and killed both adult and nymph stages of the rice plant bug. Application of the fungal strain led to an infection rate of over 70% in field populations of the pest. This biological control method has demonstrably reduced the incidence of spot rice by more than 40%, offering a sustainable solution for organic rice cultivation and safeguarding grain quality.

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The white-muscardine fungus 'BB1031' has the potential to be developed into a microbial pesticide.