Gardening Help Search

Temporary Closure

The Center for Home Gardening is currently closed to ensure staff and visitor well-being. Our Plant Doctor service is still available through e-mail. If you have any gardening questions, you can e-mail us at plantinformation@mobot.org.

Common Pests and Diseases

As summer beings to set in, the Center for Home Gardening receives an increase in the number of calls and e-mails from home gardeners asking about pest and disease issues on their plants. The first step in managing any pest or disease problem is to identify the issue and determine what may be causing it. Below are a few commonly encountered insect pests, diseases and environmental issues that one may see in June and July. Click on the link to learn more about the pest, options for treatment and view additional photos. For the full list of Common Garden Pest and Problems, click HERE. 

Insect/Animal Pests

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Aphids

Affects:
Many ornamental and tree species


Deer

Affects: 
Many ornamental species


Bagworms

 Primarily Affects:
Arborvitae, red cedar & juniper


Rose Slugs (Sawflies)

Primarily Affects:  
Roses

Japanese Beetles

Affects:
Many ornamental species



​Squash Bugs

Primarily affects: 
All cucurbits - Cucumbers, pumpkins, squash, watermelon, etc.
 

Diseases


Black Spot of Rose

Affects: Roses

 


Fireblight

Primarily Affects:
Rose family plants - Apple, crabapple, hawthorn, pear, flowering quince


Cedar Apple Rust

Primarily Affects: 
Red cedar (Juniperus virginiana), apples, crabapples; sometimes pears, quince and serviceberry


Powdery Mildew

Affects: Many ornamental plants

 

Environmental Issues


Drought and Water Stress
Seasonal Gardening Tips
  • Fertilize container plants every 2 weeks with a water-soluble solution.
     
  • Keep deadheading spent annual flowers for continued bloom.
     
  • Hot, dry weather is ideal for spider mite development. With spider mite damage, leaves may be speckled above and yellow below. Evergreen needles appear dull gray-green to yellow or brown. Damage may be present even before webs are noticed.
     
  • Fall webworms begin nest building near the ends of branches of infested trees. Prune off webs. Spray with Bt if defoliation becomes severe.
     
  • Divide bearded iris now.
     
  • Water lawns frequently enough to prevent wilting. Early morning irrigation allows turf to dry before nightfall and will reduce the chance of disease. 
     
  • Blossom-end rot of tomato and peppers occurs when soil moisture is uneven. Water when soils begin to dry; maintain a 2-3 inch layer of mulch.
     
  • For the fall garden, sow seeds of collards, kale, sweet corn, and summer squash as earlier crops are harvested.
     
  • Blackberries are ripening now.

Learn More

Enjoy the fragrant blooms of the Ozark Witch Hazel flowering in shrub borders or wooded areas on warm sunny days.
Repot any root-bound house plants now before vigorous growth occurs. Choose a new container that is only 1 or 2 inches larger in diameter than the old pot.
Repot any root-bound house plants now before vigorous growth occurs. Choose a new container that is only 1 or 2 inches larger in diameter than the old pot.
Gardening Help

The Center for Home Gardening is currently closed. If you have any gardening questions, you can e-mail us at
plantinformation@mobot.org.

Bloom Time Calendar

See when plants bloom at the Garden: