Aster yellows on potatoes is not as dangerous a disease as the potato blight that occurred in Ireland, but it does reduce yield considerably. It is similar to as potato purple top, a very descriptive sounding disease. It can affect numerous types of plants and is found across North America. The disease is most common in cooler, wet regions such as Idaho, Oregon and Washington. Find out how to diagnose the disease and how to prevent it from ruining your spud crop.
Recognizing Aster Yellows on Potatoes
Aster yellows is transmitted by tiny leafhopper insects. Once the disease progresses, the tubers are significantly damaged and generally inedible. Early insect control and removal of host plants around the potato garden are important contributions to reducing the spread of the disease. The symptoms are often seen in plants in the Aster family, but it also touches crops such as celery, lettuce and carrots as well as other ornamental species.
The initial signs are rolled up tip leaves with a yellowish color. Young plants will be stunted while mature plants form aerial tubers and the whole plant has a purplish cast. The leaf tissue between veins may also die, giving leaves with potato aster yellows a skeletal appearance. Leaves may also distort and twist, or develop into rosettes.
Very quickly the whole plant can wilt and fall over. The problem is more evident during periods of hot weather. The tubers become smaller, soft and the flavor is disagreeable. In commercial settings, the toll from aster yellows in potatoes can be significant.
Control of Potato Aster Yellows
A potato plant with aster yellows got the disease through a vector. Leafhoppers feed on plant tissue and can infect a plant 9 to 21 days after feeding on a diseased species. The disease persists in the leafhopper, who can then transmit it for up to 100 days. This can cause a widespread epidemic over time in large plantings.
Dry, hot weather causes leafhoppers to migrate from wild pasture to irrigated, cultivated land. There are 12 species of leaf hoppers that have the ability to transmit the disease. Temperatures over 90 degrees Fahrenheit (32 C.) seem to reduce the insect’s ability to spread the disease. Early insect control is essential to squelching the spread.
Once a potato plant with aster yellows shows symptoms, there is little to be done about the problem. Using healthy, resistant tubers can help, as can removal of old plant material and weeds from the planting bed. Never plant tubers unless they come from a reputable dealer.
Rotate crops that are susceptible to the disease. Early use of insecticides in mid-spring to early summer can significantly reduce leafhopper populations. Destroy any plants with the disease. They must be thrown out rather than added to the compost pile, as the disease can persist.
This serious disease of potatoes can be rampant without early control, resulting in diminished yields and poor tubers.