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:
“Magic is the envelopment and coercion of the objective world by the ego; it is a dynamic subjectivism. Religion is the coercion of the ego by gods and spirits who are objectively conceived beings in control of nature and man.”
—Richard Chase (b. 1914)
“Could it not be that just at the moment masculinity has brought us to the brink of nuclear destruction or ecological suicide, women are beginning to rise in response to the Mother’s call to save her planet and create instead the next stage of evolution? Can our revolution mean anything else than the reversion of social and economic control to Her representatives among Womankind, and the resumption of Her worship on the face of the Earth? Do we dare demand less?”
—Jane Alpert (b. 1947)
“Why wont they let a year die without bringing in a new one on the instant, cant they use birth control on time? I want an interregnum. The stupid years patter on with unrelenting feet, never stopping—rising to little monotonous peaks in our imaginations at festivals like New Year’s and Easter and Christmas—But, goodness, why need they do it?”
—John Dos Passos (1896–1970)