7 articles tagged "Root, Tuber, and Bulb Crops".

Figure 1: Cercospora leaf spot of garden beet causes bray/brown lesions with reddish margins.

This disease was observed in southern Indiana recently. Cercospora leaf spot affects table beets and swiss chard. Symptoms include circular leaf spots that may have a reddish margin. The center of the lesions may start off a light brown and turn to gray after the fungus (Cercospora beticola) begins to sporulate. Under conditions conducive to disease, the lesions can coalesce and result in loss of foliage. Yield and quality of the crop can be reduced. Cercospora leaf spot is favored by rainy weather or overhead irrigation and temperatures from 77 to 95°F.  The spores are readily dispersed in rainy, windy weather. Resistant cultivars are available. Fall tillage and crop rotations of 2 to 3 years should help to lessen disease severity. Several fungicides are listed in the 2017 Midwest Vegetable Production Guide for Commercial Growers including copper compounds, some of which may be allowed in organic certifications. Synthetic fungicides include:[Read More…]


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Daikon radish is a member of Brassica family. It forms a large white tap root like a giant carrot. The tap root (12 to 20 inches long and 2 to 4 inches in diameter) penetrates into the soil leaving 2 to 6 inches protruding above ground.  Radishes are cool-season crops. They are best grown with air temperatures in the range of 50 to 65°F. They grow fast, forming a dense canopy in the fall.  They are winter killed when temperatures drop to low 20s °F for a few consecutive nights. Daikon radish is a common and popular vegetable consumed in the southeast and Eastern Asia (Figure 1). The large and white roots have a favorable mild flavor, very low calorie content and rich in vitamin C. Fresh or picked diced daikon roots are important ingredients in a variety of dishes and soups in Asia cooking. Leaves are also consumed as[Read More…]


Last fall, my lab received a carrot sample with disease-like lesions (Figures 1 and 2). There are at least 3 carrot diseases that may appear similar. These diseases are: Alternaria leaf blight (late blight), Cercospora leaf spot (early blight) and bacterial leaf blight. Often an examination in the laboratory is necessary. My examination revealed the characteristic spores (conidia) of Alternaria dauci, causal agent of Alternaria leaf blight. Figure 1  shows a stand of carrots with several leaves that appear chlorotic (yellow) and necrotic. A closer examination reveals small lesions on the leaves (Figure 2). Loss of leaves may lead to fewer or smaller carrots. Sometimes severe infections can lead to the premature separating of the leaves and root. Alternaria leaf blight can be rapidly spread between plants by the conidia that are produced on the plant surface. I could easily find these spores on the surface of the carrot leaves brought to my lab. The conidia may[Read More…]


Three species of seed and root maggots attack vegetables in Indiana. The seedcorn maggot (Figure 1) feeds on seeds and seedlings of sweetcorn, cucurbits, lima and snap beans, peas, and other crops. Cabbage maggots can cause serious damage to transplants of cabbage, broccoli, cauliflower, and Brussels sprouts and make the fleshy roots of radishes, turnips, and rutabagas unmarketable. Onion maggots are pests of seedling onions, developing bulbs and onions intended for storage. Seedcorn maggot flies emerge in April and May and lay eggs preferentially in areas with decaying organic matter. Fields that are heavily manured or planted to a cover crop are more likely to have seedcorn maggot injury. Maggots burrow into the seed and feed within, often destroying the germ. The seeds fail to germinate and plants do not emerge from the soil, leaving gaps in the stand. When infested seeds germinate, the seedlings are weak and may die.[Read More…]


I’ve seen some substantial populations of potato leafhoppers recently. Leafhoppers can be a significant pest of a number of vegetable crops, with potato and snap beans being particularly affected. Look for adults flitting off the plants when they are disturbed and for nymphs feeding on the underside of the leaves. It is important not to wait until you see symptoms (hopper burn) before you take action. Scouting is the best way to avoid leafhopper injury.


​The cool, wet weather we have been having is perfect for the root and seed maggots in early planted vegetables. I have already received calls about onion maggots. If you are planting early vegetables, check out the article in the March 19 issue of the Hotline for 2015. So, how do we define early planted vegetables? With regard to root and seed maggots, anything that you plant before the soil temperatures reach about 70°F is subject to attack from the flies. Of course, not every field will suffer damage but the potential is there. The use of black plastic mulch will heat up the soil more quickly and may help to reduce root and seed maggot damage.


​Three species of seed and root maggots attack vegetables in Indiana. The seedcorn maggot feeds on seeds and seedlings of sweet corn, cucurbits, lima and snap beans, peas, and other crops. Cabbage maggots can cause serious damage to transplants of cabbage, broccoli, cauliflower, and Brussels sprouts and make the fleshy roots of radishes, turnips, and rutabagas unmarketable. Onion maggots are pests of seedling onions, developing bulbs and onions intended for storage. Seedcorn maggot flies emerge in April and May and lay eggs preferentially in areas with decaying organic matter. Fields that are heavily manured or planted to a cover crop are more likely to have seedcorn maggot injury. Maggots burrow into the seed and feed within, often destroying the germ. The seeds fail to germinate and plants do not emerge from the soil, leaving gaps in the stand. When infested seeds germinate, the seedlings are weak and may die. Maggots[Read More…]


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