Potato Diseases & Pests Management

The historically significant Phytophthora infestans (late blight) remains an ongoing problem in Europe and the United States. Other potato diseases include Rhizoctonia, Sclerotinia, black leg, powdery mildew, powdery scab and leafroll virus.

Insects that commonly transmit potato diseases or damage the plants include the Colorado potato beetle, the potato tuber moth, the green peach aphid (Myzus persicae), the potato aphid, beet leafhoppers, thrips, and mites. The potato cyst nematode is a microscopic worm that thrives on the roots, thus causing the potato plants to wilt. Since its eggs can survive in the soil for several years, crop rotation is recommended.

Main Diseases & Pests on Potato and Management 

Many similar diseases and pests occur on POTATO and TOMATO, with the similar treatment.  

Diseases & Control

Early blight:  

Caused by fungi.  Also occur on tomato, pepper and eggplant. Appears on leaves and potato tubers 

Manzgement:  

        - Choose disease-free seeds and plants

        -  Maintain plant health through proper water and fertilization regimes; N and P deficiencies increase susceptibility to early blight.

        - Garden areas should be rotated out of potatoes, tomatoes, pepper and eggplant for 3-4 years so that hosts of the disease are not present.

        - Chemicals:  Mancozeb, chlorothalonil and copper are effective against early blight when applied at approximately 7-10 days intervals. Spraying should commence at the first sign of disease or immediately after bloom.

Late blight:  

Leaves have large, dark brown blotches with a green gray edge; not confined by major leaf veins.  Infections progress through leaflets and petioles, resulting in large sections of dry brown foliage. Stem infections are firm and dark brown with a rounded edge.

Management: 

        - Propamocarb 72.2sl, Cymoxanil +Mancozeb 72wp, Phosethyl-al 80wp, Dimethomorph 50wg  

        - Rotate fungicide groups and/or tank mix fungicides to avoid producing fungicide-resistant isolates. 

 

Insects/Pests & Control

Potato aphid / whitefly:  

Imidachorprid 20sl, 70wp/wg,  Thiamethoxam 25wg,  Acetamiprid 25wp

Potato bettle:  

Both larvae and adults feed on the foliage of potatoes and, if left untreated, can completely defoliate plants. Also occur on eggplant, tomato, pepper, and other plants.

Management:  Esfenvalerate 5ec, Cypermethrin 10ec, Azadirachtin 0.3ec – None resistant , Spinosad 48sl - None resistant