Cause Fusarium proliferatum, a fungus.
Symptoms This rot of onion bulbs in storage shows symptoms similar to the neck rot. Symptoms usually start at the neck and progress down along the fleshy scales, but the basal plate is not affected. Infected scale appears faint yellow, water-soaked, and translucent, later turning tan-brown and soft. Occasionally, a white mold grows between rotten scales. Frequently, the rot appears to progress along a single fleshy scale in the bulb, although rotting of all the scales in a bulb also has been observed. Usually, infected bulbs do not show any pronounced external symptoms or signs of the fungus.
Control At present, no control measures are known, because the mode of infection and conditions that favor infection and disease development in storage are not well understood.
Biological control Efficacy unknown in the Pacific Northwest.
- Amplitude at 3 to 4 quarts/A as a soil drench on 10- to 21-day intervals. Preharvest interval is 0 days. 4-hr reentry. O
- Prestop at 1.4 to 14 oz/10 gal water (0.1% to 1.0% suspension) as a soil drench or incorporation into growing medium. 0-hr reentry. O
- Stargus at 6 to 8 fl oz per 1,000 ft row as an in-furrow treatment, or 3 to 4 quarts/A as a soil drench (drip or chemigation) on 10- to 21-day intervals. Preharvest interval is 0 days. 4-hr reentry. O