Anthracnose of Cucurbits

Colletotrichum orbiculare

Description:

A fungus causing red brown to black, circular spots with water soaked edges on the leaves. The leaf often tears along the spots. On stems the lesions are more elongated and sunken. Under moist conditions the lesions may ring bark the stem causing the runner to wilt and die. On fruit the spots may not appear until after harvest and when in storage. Masses of pink spores may be produced from the round sunken lesions on the fruit.

Species Affected:

Cucumber, Marrow, Pumpkin, Rockmelon, Watermelon.
Most common on Watermelon.

Biology:

Spread by raindrop splash, on seed and by workers, implements and animals.

Life Cycle:

Origin and History:

Distribution:

Significance:

Reduces yields and storage time.

Management and Control:

Use healthy seed.
Destroy crop residues.
Rotate with unrelated crops and avoid continuous cropping with Cucurbits.
Don't crop areas that have been infected for 4 years.
Control Cucurbit weeds in and around crop.
Fumigate infected areas.
Avoid working in diseased areas, especially when wet.
Apply fungicides.

Related and Similar Species:

Bacterial Leaf Spot - tends have dead patches on the leaf that falls away rather than tearing along the spots.

References:

1291

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.