If using DROP or DIP for size control, do not let humidity rise above 90%.Ĭhemical control Best used with cultural controls. Heating in the morning before sunup can also help prevent dew formation as air temperature increases faster than the temperature of plant parts. Heating the greenhouse at night (especially for zero or negative DIF) or venting around sunset may be necessary. In the greenhouse, maintain a steady, relatively dry environment by keeping greenhouse humidity below 90%, increasing spacing between plants for good air circulation, and taking care not to splash water on foliage during watering.Rotate planting sites to new ground each year.Individual drip watering of pots can also help. Avoid overhead irrigation or any practice that keeps plants wet for extended periods of time.Reduce planting densities to promote good air circulation.Removing flower buds early helps manage disease.Preferably, pull shoots as soon as they can be pulled away easily from bulbs. Remove all plant debris at season's end.Dead tissue may be covered with the fuzzy gray growth and sporulation of the fungus during moist periods. Flowers develop tan-to-brown spreading spots on buds and petals. Disease severity is generally greatest on the lower leaves. As the spots increase in size the foliage is killed and hangs down. Yellow streaks are often associated with these spots. Spot color varies with leaf texture and the lily species affected, but usually the center is a different color and slightly sunken. Symptoms Typical initial symptoms are water-soaked (wet-looking), teardrop- or boat-shape brown spots that occur anywhere on the leaf. Cultivars are known to differ in susceptibility. The disease can reduce bulb growth as well as making cut flowers or pot grown plants unmarketable. Injuries due to hail can also favor disease development. Colonized flower parts that fall onto leaves or stems can be the source of mycelium that directly infects healthy tissues. Under optimal conditions many spots may occur at once throughout the planting. Spore production in diseased tissue spreads the fungus during the growing season. elliptica is through stomata on the underside of leaves. Infection is most likely in wet foggy weather where plants are wet for 6 to 12 hours and when temperatures range from 50☏ to 65☏ during day or night. Conidia are windblown to healthy foliage. In spring, sclerotia on or near the soil surface produce conidia that infect leaves. Botrytis overwinters as sclerotia in the debris of plant shoots that mature and decay in fall. The former has been reported on crocus, daylily, and gladiolus but is primarily on lily while the latter has a huge host range.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |