This list will help you learn about common pests and diseases and how to identify them.
Aphids
Aphidshave infested this scabiosa plant.
Spraying with a jet of water and/or insecticidal soap gets rid of the problem.
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Repeated sprayings will probably be necessary.
Cabbage Worms
Holes in cabbage leaves are a telltale sign ofcabbage wormfeeding.
Hand-remove adults and look for eggs on the undersides of the leaves.
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Spider Mites
This boxwood suffered a severespider miteinfestation, causing theleaves to dry outand die.
Spraying with horticultural soap controls spider mites.
Squash Bugs
Squash bug eggsare hatching into nymphs on the undersides of these leaves.
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Remove any affected leaves and scout for adults.
Tomato Hornworms
The tomato hornworm is the larval stage of the five-spotted hawk moth.
Hornworms favor the leaves of tomato and pepper plants.
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Whiteflies
Whitefliesfeed off plants by sucking the plant’s juices.
Sprays containing pyrethrum orneemoffer some controlto existing whitefly infestations.
Coat both the upper and lower surfaces of leaves.
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Repeat applications will likely need to be made.
Wireworms
Wireworms are very common in most types of soil and can be found year-round.
If wireworms feed on the roots of plants, the plants will grow slowly and will be weak.
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Since wireworms are so common, they are extremely hard to control.
The spread of bacterial wilt can be deadly and quick.
It starts with one leaf wilting and spreads.
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It affects squash, too, but to a much lesser extent.
If an infestation still occurs, use a pesticide such as Rotenone or Pyrethrum on your plants.
Plant Viruses
Mottled yellow leaves usually indicate a mosaic virus.
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Remove and destroy any affected plants as soon as possible to limit the spread of the virus.
Remove and destroy any affected leaves.
Powdery Mildew
Powdery mildewhas formed on the leaves of this rudbeckia.
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If you see it on any of your plants, use a fungicide to control the problem.
Leaf Spot
The lower leaves of this tomato plant are infected withleaf spot.
Aphids.University of Kentucky Extension
Twospotted Spider Mites in Home Gardens.
Scot Nelson / Flickr / CC BY 1.0
Squash Bugs in Home Gardens.
“Safe And Natural Insecticides”.North Dakota State University, 2016, https://www.ag.ndsu.edu/yardandgardenreport/2016-07-29/safe-and-natural-insecticides.
Whiteflies Management Guidelines–UC IPM.
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Cucumber Beetles in Home Gardens.
Botrytis or Gray Mold.Penn State Extension,
Powdery Mildews.University of Colorado Extension
Leaf Spot Diseases of Trees and Shrubs.
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