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Look for fruit rot on pumpkins and squash

M.Grabowski, UMN Extension

Photo 1: Anthracnose fruit rot on winter squash

Michelle Grabowski, UMN Extension Educator

Although most pumpkins and winter squash are not yet ready to harvest. It is important to keep a close eye on the developing fruit. Many different kinds of fungal pathogens can rot winter squash and pumpkins before they are ripe. There are a few things that a gardener can do to prevent wide spread loss.

Weed the pumpkin patch! Weeds crowd growing fruit and create a moist shaded environment that fungal pathogens thrive in. Removing weeds from the garden allows better air flow around the developing fruit. This way the new pumpkins and squash will dry out quickly after rain or irrigation.

Remove any infected squash from the garden. Many fungal fruit rot diseases are easily splashed from one fruit to another on rain or irrigation. If one fruit is infected, the rotted area or the spots on the fruit will produce spores from now until harvest. If left in the garden, the disease will continue to spread to other developing squash and pumpkins. Infected fruit can be thrown in the compost pile if it heats up or take it to a municipal compost site.

M.Grabowski, UMN Extension

Photo 2: Butternut squash overrun with weeds

Elevate squash and pumpkins on wet heavy soils. Some fungal pathogens will infect developing pumpkins and squash from underneath, where the fruit is sitting on the soil. These bottom rots are common on heavy wet soils. Remove any squash and pumpkins that are already rotting. Elevate remaining healthy fruit on a layer of airy mulch like straw or wood chips to improve air circulation and reduce contact with soil. Be careful not to injure fruit. In the future consider growing plants on raised beds to improve drainage.

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