![]() ![]() Can be applied up to and on the day of harvest. Iprodione 4L AG at 1.5 to 2 pint/A plus another fungicide with a different mode of activity.Hi-Yield Captan 50 W Fungicide may be used in home gardens at 1 to 2 Tbsp/gal water.Fontelis at 16 to 24 fl oz/A plus another fungicide.Can be used up to and including the day of harvest. Avoid use when honey bees are active due to larval toxicity. Bonide Captan 50 WP at 1 to 2 Tbsp/gal water can be used in home gardens.Surveys in Oregon found Botrytis resistant to FRAC groups 7, 9, and 17. Strains resistant to several different modes of action have been reported from throughout the world including PNW. Minimize the use of any one group during the growing season. Alternate or tank-mix materials from different groups with different modes of action to avoid problems with resistant strains. A preharvest application is useful to control fruit rot after harvest if wet weather is forecasted. Pick fruit at correct stage of maturity and move harvested fruit to cold storage as soon as possible.Ĭhemical control Apply fungicide from prebloom through the end of bloom.Avoid late-season fertilization that stimulates growth susceptible to winter injury.Adjust timing and/or frequency of overhead irrigation to keep aboveground portions of the plant dry.Space plants for good air circulation and quick drying.Annually prune to remove infected twigs and to open canopy for good air circulation.The disease is easily confused with bacterial blight and/or the shoot blight stage of mummy berry if there is no sporulation. Symptoms can be seen after winter injury and/or before floral budbreak. Black sclerotia can be found near the tip of blighted twigs. Twigs blight from the tip toward the base. Infected succulent twigs are at first brown to black and later bleach to tan or gray. Fruit may also shrivel and be covered with the characteristic gray sporulation after harvest. The entire berry rots and shrivels, then falls off the cluster. Brown necrosis spreads such that whole sectors of the berry are involved. Green fruit rot starts as a brown water-soaked discoloration near the calyx end of the fruit. On young leaves, pale brown lesions form. The disease also can move from blossoms back into fruit-producing wood. Infections may move through the blossoms rapidly and often destroy the entire floral structure. Blossoms may be covered with dense grayish powdery masses of Botrytis spores. Symptoms During wet springs, blueberry blossoms take on a brown, water-soaked appearance and die. Also, branch tips killed by low winter temperatures are easily infected. Infection is more likely on fruit that retains old floral tissue (which is varietal dependent and increases with higher humidity). Green fruit can rot when rains continue into the late spring and early summer. Cultivars that tend to retain floral structures over a long period are more susceptible. Susceptibility is highest during bloom and again near harvest. Spores spread primarily by wind but also by splashing water. In spring, infected tissues produce vast numbers of spores during wet periods. This species is naturally resistant to the FRAC group 17 fungicide fenhixamide. Migration of Botrytis between fields in the PNW, however, was shown to be low.Ī related species Botrytis pseudocinerea, has been reported from a low number of rotted fruit in California. Blueberry fields in Florida that were within 50 feet of strawberry fields had a higher incidence of Botrytis diseases. Many different fruit (such as blackberry, raspberry, and strawberry) and ornamental crops are susceptible to infection and may be sources of spores. It also overwinters as a saprophyte on dead organic matter and dead plant parts in or on the soil surface. Cause Botrytis cinerea, a fungus that survives as sclerotia (resistant survival structure) and dormant mycelia on dead twigs of bushes and prunings or in fruit left on the bush. ![]()
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