Diseases and Pests of Perilla and Their Control Methods

Diseases of Perilla

Leaf spot

Leaf spot usually occurs from June to harvest, harming the growth of perilla.

Initially, small brown or dark brown spots of different sizes and shapes appear on the leaf surface, and then develop into large round or polygonal spots, generally with a diameter of 0.2-2.5 cm.

The spots are not obvious on purple leaves, but are more obvious on green leaves. After drying, holes are often formed. In severe cases, the spots merge and the leaves fall off.

Prevention and treatment methods

When selecting seeds, choose from disease-free plants.

Pay attention to soil drainage and avoid over-planting.

Starting from the early stage of the disease, spray with 800 times diluted 80% wettable mancozeb, or 1:1:200 Bordeaux mixture. Spray 2-3 times every 7 days. However, spraying should be stopped half a month before harvest to ensure that the medicinal materials are free of pesticides.

Pests of Perilla

Red Spider

It is most likely to occur during the dry months of June to August when the humidity is high.

Adult red spider mites are small, usually orange-red, sometimes yellow. Red spider mites gather on the back of the leaves to suck sap. Initially, yellow-white spots appear on the leaves, and later larger yellow-brown spots can be seen on the leaves.

As the spots expand, the entire leaf turns yellow and falls off.

Prevention and treatment methods

During the outbreak period, spray with 2000 times diluted 40% dimethoate emulsion as early as possible. However, it is required to stop spraying pesticides half a month before harvest to ensure that no residual poison remains on the medicinal materials.

Spodoptera exigua

From July to September, the larvae harm the growth of perilla, and the leaves will be bitten into holes. The mature larvae will pupate in thin silk cocoons on the plants.

Prevention and treatment methods

Spray with 1000 times diluted 90% crystalline trichlorfon.