Japan flags higher pest pressure for fruit and vegetables

Japan’s Ministry of Agriculture, Forestry and Fisheries issued its fourth pest and disease forecast for fiscal 2026 on 8 July. The outlook combines information supplied by prefectural authorities with weather conditions, crop development and field-survey results. MAFF noted that the risks apply to parts of the listed regions and not necessarily to every production area within them.

Caterpillar pests threaten vegetable crops

MAFF expects above-normal numbers of cotton bollworm in parts of Hokkaido, northern Tohoku, Tokai and Kinki. Moderately elevated levels are also forecast in southern Tohoku, northern Kanto, Koshin and Shikoku.

Beet armyworm pressure is expected to be high in parts of Hokuriku, Tokai and Kinki, and moderately high in northern Tohoku and Shikoku. Prefectural advisories have already been issued for the two pests in several areas, including Hokkaido, Toyama, Aichi and Osaka.

The larvae can enter fruit, flower buds and developing heads, making them difficult to control once established. MAFF therefore recommends frequent crop inspections and treatment at an early stage. Protected-crop growers are also advised to use insect screens at greenhouse openings.

Reduced sensitivity to some insecticides has been reported. Producers should avoid repeatedly using products from the same chemical group and follow regional guidance when selecting treatments.

Whitefly numbers on tomatoes are forecast to be moderately high in parts of southern Tohoku, northern Kanto and southern Kyushu. Thrips affecting leeks may also exceed normal levels in northern Tohoku, Koshin and Kinki.

Fruit orchards placed under stink bug watch

Fruit-tree stink bugs are forecast to be more numerous than usual in parts of northern Kanto, Hokuriku, Tokai, Kinki, Chugoku, Shikoku and Kyushu. Moderately high levels are expected in Tohoku and Koshin, while Ishikawa Prefecture has issued an advisory.

MAFF said warmer conditions since spring contributed to heavy movement into orchards in areas with large overwintering populations. Future pressure will also depend on stink bug numbers and the availability of cones on cedar and cypress trees.

Growers are advised to monitor incoming insects closely and begin control measures when they are first detected. MAFF said evening spraying can be effective because the pests are most active from dusk into the night. Coordinated treatment across neighbouring orchards may also improve control.

The forecast additionally points to high apple Alternaria blotch pressure in parts of northern Kanto, with moderately high levels in Hokkaido and Tohoku. Pear scab is expected to be moderately high in southern Tohoku, northern Kanto and Kinki.

MAFF urged producers to consult the latest prefectural forecasts, inspect fields and orchards regularly, and carry out preventive or control measures at the appropriate crop and pest-development stage.

source and photo: maff.go.jp