Remember that Devrinol may only be applied once per season, and that moisture will be required for incorporation, but if groundsel is your problem, this may be a critical time to use Devrinol. This Labour Day herbicide application timing should reduce many of these problems weeds for next year. Two fungal diseases have shown up this summer at higher levels than last year due to the rainy weather this past spring. Both anthracnose and spur blight are fungal diseases spread by rain splashed spores. However, they differ in appearance, biology and life cycle.
Anthracnose spores infect young green tissue during wet periods.
Lesions may take up to a month or more to develop. The lesions on canes observed now were actually caused by infections a while ago. Infection and lesion development can occur on all tissue including leaves, flowers, fruit, and petioles but are most conspicuous on primocanes. The disease first appears as reddish purple, circular to elliptical spots that eventually become sunken with a grey or tan center. As the disease develops, summer spores are produced within the lesion and spread to other tissue the next time it rains.