Symptoms or Damage Management Pests Pink Root Infected roots first turn light Avoid repeated cropping of Phoma terrestris pink, then darken through onion on the same soil, use of bulb. red and purple, shrivel, turn resistant varieties, good soil black, and die. The pinkish tilth and fertility, control of red discoloration may extend insects and other diseases to up into the scales of the bulb. maintain healthy plants, and New roots also may become preplant soil fumigation. infected. If infection continues, plants become stunted. Many weak Fusarium species can also cause pink roots, Pink root is primarily a problem on onion; garlic is infected by the pink root organism. Downy Mildew, Downy mildew can infect Cultural Control- Use Peronospora both onions and garlic. The disease-free bulbs, sets, and destructor first evidence of disease is a seed. Use a 3-year rotation fine, furry, grayish white to away from Allium crops in purple growth on the fields where the disease has surface of older leaves. Leaf occurred. Destroy tissue under the growth volunteer Allium plants in becomes pale green, then and around the field and yellow, and finally collapses. buildings. Currently there Large, yellowish, circular are a few red onion cultivars clumps of infected plants, a (e.g., Calred) that are few to many feet in resistant to downy mildew. diameter, may be the first Chemical Control-Spray at symptom noticed in the the first sign of disease; field. The often enlarge in fungicides may be applied the direction of prevailing on a 7-day schedule, if winds. necessary. For all fungicides, The disease can develop thorough coverage of foliage from an initial infection by is important in the control of airborne spores into an downy mildew epidemic very quickly if humidity and temperature conditions. Initial sources of disease can be infected bulbs, sets, seeds, and plant debris.
Pests Symptoms or Damage Management Pink Root Phoma terrestris bulb. Infected roots first turn light pink, then darken through red and purple, shrivel, turn black, and die. The pinkish red discoloration may extend up into the scales of the bulb. New roots also may become infected. If infection continues, plants become stunted. Many weak Fusarium species can also cause pink roots, Pink root is primarily a problem on onion; garlic is infected by the pink root organism. Avoid repeated cropping of onion on the same soil, use of resistant varieties, good soil tilth and fertility, control of insects and other diseases to maintain healthy plants, and preplant soil fumigation. Downy Mildew, Peronospora destructor Downy mildew can infect both onions and garlic. The first evidence of disease is a fine, furry, grayish white to purple growth on the surface of older leaves. Leaf tissue under the growth becomes pale green, then yellow, and finally collapses. Large, yellowish, circular clumps of infected plants, a few to many feet in diameter, may be the first symptom noticed in the field. The often enlarge in the direction of prevailing winds. The disease can develop from an initial infection by airborne spores into an epidemic very quickly if humidity and temperature conditions. Initial sources of disease can be infected bulbs, sets, seeds, and plant debris. Cultural Control- Use disease-free bulbs, sets, and seed. Use a 3-year rotation away from Allium crops in fields where the disease has occurred. Destroy volunteer Allium plants in and around the field and buildings. Currently there are a few red onion cultivars (e.g., Calred) that are resistant to downy mildew. Chemical Control-Spray at the first sign of disease; fungicides may be applied on a 7-day schedule, if necessary. For all fungicides, thorough coverage of foliage is important in the control of downy mildew
Garlic.docx