Organic Control of Anthracnose Leaf Spot in Gooseberry

View the project final report

Commodities

• Fruits: berries (other)

Practices

• Crop Production: varieties and cultivars
• Pest Management: biorational pesticides, botanical pesticides, cultural control
• Production Systems: organic agriculture

Although gooseberries are not a common food in our region, they are a promising new crop which produces a flavorful fruit suited for fresh eating and processing.  Along with other organic fruit farmers in the region, we have grown gooseberries but found that the Anthracnose leaf spot disease is extremely devastating: it defoliates plants by mid-late summer in most years, increases over the years as a planting ages, and appears to greatly reduce plant vigor and yield.  We have observed that varieties differ in susceptibility and that trellising the plants may lessen the severity of the disease, but we have not found a truly effective organic control that is environmentally benign and effective.  Over two growing seasons, we have measured the effects of several factors on disease severity:

1. Gooseberry variety
2. Training method (freestanding bush vs. cordon trellis)
3. Organic spray regimen (potassium bicarbonate, copper soap plus Bacillus amyloliquefaciens, Reynoutria sachalinensis extract, and no sprays)

We studied multiple factors because it is likely that a combination of all three factors may be required for effective control. 

Main conclusions from our research are that gooseberry varieties vary dramatically in susceptibility to Anthracnose, trellising marginally reduces the diseases, and that sprays of copper soap plus Bacillus amyloliquefaciens or Reynoutria sachalinensis extract reduce the disease.  We disseminated these results extensively through online webinars, a field day at our farm, publications in regional and national periodicals, email list servs, an online discussion group and an email newsletter.

1. Measure the susceptibility of four common gooseberry varieties to Anthracnose leaf spot.

2. Measure the effect of training method (cordon trellis or freestanding bush) on Anthracnose incidence.

3. Measure the effect of three organic sprays on Anthracnose incidence, compared to an unsprayed control.

4. Share findings through conference presentations, written reports, and an online video.