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:
“The poets were not alone in sanctioning myths, for long before the poets the states and the lawmakers had sanctioned them as a useful expedient.... They needed to control the people by superstitious fears, and these cannot be aroused without myths and marvels.”
—Strabo (c. 58 B.C.–c. 24 A.D., Greek geographer. Geographia, bk. 1, sct. 2, subsct. 8.
“Above and beyond paying attention to feelings before and after a separation, never threaten your child with leaving or loss of love in an effort to control her behavior. Children believe their parents’ assertions that “I will send you away,” “I won’t love you any more,” “I’ll go away,” and are terrified with good reason. Fear is a very poor way of disciplining a child, and it can cause severe lifelong anxiety.”
—Alicia F. Lieberman (20th century)
“Who can control his fate?”
—William Shakespeare (1564–1616)