Control
In affected orchards, new infections can be reduced by removing leaf litter and trimmings containing infected tissue from the orchard and incinerating them. This will reduce the amount of new ascospores released in the spring. Additionally, scab lesions on woody tissue can be excised from the tree if possible and similarly destroyed.
Chemical controls can include a variety of compounds. Benzimidazole fungicides (e.g., Benlate ) work well but resistance can arise quickly; Similarly, a number of chemical classes including sterol inhibitors such as Nova 40, and strobilurins such as Flint among others, were used extensively but are slowly being phased out because of resistance problems.
Contact fungicides not prone to resistance such as Captan are viable choices. Copper or Bordeaux mixture are traditional controls but are less effective than chemical fungicides and can cause russeting of the fruit. Wettable sulfur also provides some control. The timing of application and concentration varies between compounds.
15 genes have been found in apple cultivars that confer resistance against apple scab. Researchers hope to use cisgenic techniques to introduce these genes into commercial cultivars and therefore create new resistant cultivars. This can be done through conventional breeding but would take over 50 years to achieve.
Read more about this topic: Apple Scab
Famous quotes containing the word control:
“There are many things children accept as “grown-up things” over when they have no control and for which they have no responsibility—for instance, weddings, having babies, buying houses, and driving cars. Parents who are separating really need to help their children put divorce on that grown-up list, so that children do not see themselves as the cause of their parents’ decision to live apart.”
—Fred Rogers (20th century)
“Just as men must give up economic control when their wives share the responsibility for the family’s financial well-being, women must give up exclusive parental control when their husbands assume more responsibility for child care.”
—Augustus Y. Napier (20th century)
““Have we any control over being born?,” my friend asked in despair. “No, the job is done for us while we’re sleeping, so to speak, and when we wake up everything is all set. We merely appear, like an ornate celebrity wheeled out in a wheelchair.” “I don’t remember,” my friend claimed. “No need to,” I said: “what need have us free-loaders for any special alertness? We’re done for.””
—Marvin Cohen, U.S. author and humorist. The Self-Devoted Friend, New Directions (1967)