Gardening can be such an enjoyable, relaxing hobby. Numerous studies have explored how fresh air, soil, plants, and physical activity in the garden benefit both physical and mental health – not to mention the healthy bounty of homegrown vegetables and herbs. But when garden pests and diseases threaten your precious plants, gardening quickly becomes a disheartening and stress-filled activity. Learn how to treat and prevent common pests and diseases in the garden so you can enjoy, not dread, walking among your plants again.
The following guide is divided by vegetables, herbs, and flowers, and includes links to helpful articles on the pests and diseases of individual plants.
Pests and Diseases in the Vegetable Garden
From beets to zucchini, learn about the pests and diseases that plague each vegetable, as well as how to treat and prevent these problems.
Beet pests and diseases
A wonderfully versatile vegetable, beets can be grown for their greens as well as their roots, and they’re rich in nutrients.
Pests:
- beet cyst nematode
- root knot nematode
- darkling beetle
- leafminers
Diseases:
- bacterial blight
- scab
- beet curly top disease
- beet western yellow virus
- cercospora leaf spot
- damping off
- downy mildew
- fusarium wilt and root rot
- powdery mildew
Brassica pests and diseases
Pests:
- cabbage worms
- diamondback moth caterpillar
- cabbage looper
- harlequin bug
- imported cabbageworm
- armyworms
- aphids
- silverleaf whitefly
Diseases:
- black rot
- clubroot
- downy mildew
- leaf spot
- powdery mildew
- white blister
- flea beetles
- aphids
Carrot pests and diseases
Pulling this classic root vegetable out of the soil is immensely satisfying, so make sure your carrot crop remains healthy!
Pests:
- aphids
- carrot rust fly
- carrot weevil
- flea beetle
- root-knot nematodes
- wire worms
Diseases:
- Alternaria blight
- black rot
- cercospora blight
- cottony rot
- downy mildew
- powdery mildew
- bacterial leaf blight
- soft rot
- cavity spot
- damping-off
Cucumber pests and diseases
Eaten fresh from the garden (maybe with a little salt!) or as pickles year-round, cucumbers have a wonderfully refreshing crunch.
Pests:
- aphids
- cabbage looper
- cucumber beetles
- cutworms
- flea beetles
- stinkbugs
- thrips
Diseases:
- Alternaria leaf blight
- anthracnose
- belly rot
- cercospora leaf spot
- downy mildew
- fusarium wilt
- gummy stem blight
- powdery mildew
- septoria leaf spot
- target leaf spot
- verticillium wilt
- angular leaf spot
- bacterial leaf spot
- bacterial wilt
- aster yellows
- cucumber green mottle mosaic
- cucumber mosaic
- squash mosaic
- watermelon mosaic
- phytophthora blight
- Pythium fruit rot
- scab
Leek pests and diseases
Something like a giant green onion, leeks add excellent flavor to soups and many other dishes.
Pests:
- leafminers
- onion maggot
- thrips
Diseases:
- botrytis leaf blight
- damping-off
- downy mildew
- pink root
- purple blotch
- white rot
Lettuce pests and diseases
This leafy green is a must-have for salads and sandwiches.
Pests:
- aphids
- cutworms
- slugs and snails
Diseases:
- anthracnose
- leaf drop
- powdery mildew
- septoria leaf spot
- big vein
- bottom rot
- downy mildew
Onion pests and diseases
Onions are used to flavor many savory dishes and come in a wide variety of types to suit the need, from green onions to storage onions.
Pests:
- bulb mites
- leafminers
- onion maggot
- thrips
Diseases:
- black mold
- botrytis leaf blight
- downy mildew
- fusarium basal plate rot
- fusarium damping-off
- purple blotch
- rust
- smut
- white rot
- leaf streak and bulb rot
- onion yellow dwarf
- Pythium seed rot
Potato pests and diseases
This starchy, crowd-pleasing root vegetable fits in at every meal, making it a great choice for the vegetable garden, too.
Pests:
- aphids
- Colorado potato beetle
- cutworms
- flea beetles
- wireworms
Diseases:
- bacterial ring rot
- blackleg
- common scab
- black dot
- black scurf and rhizoctonia canker
- gray mold
- pink rot
- potato early blight
- powdery scab
- verticillium wilt
- potato late blight
- potato leaf roll
- potato virus
Pumpkin pests and diseases
Whether for decorations or pies, pumpkins deserve a place in every fall vegetable garden.
Pests:
- aphids
- armyworms
- cabbage looper
- cucumber beetles
- cutworms
- flea beetles
- squash bug
- squash vine borer
- thrips
Diseases:
- Alternaria leaf blight
- Alternaria leaf spot
- cercospora leaf spot
- downy mildew
- fusarium crown and foot rot
- gummy stem blight
- powdery mildew
- septoria leaf spot
- southern blight
- verticillium wilt
- angular leaf spot
- bacterial leaf spot
- bacterial wilt
- aster yellows
- cucumber mosaic
- squash mosaic
- watermelon mosaic
- zucchini yellow mosaic
- phytophthora blight
Sweet potato pests and diseases
This versatile root vegetable can be used in everything from soups to desserts and is surprisingly easy to grow.
Pests:
- sweet potato stem borer
- white grub
Diseases:
- Alternaria leaf spot and leaf and stem blight
- black rot
- fusarium root and stem rot
- bacterial soft rot
- bacterial wilt
- leaf and stem scab
- pox
- sweet potato virus disease
Tomato pests and diseases
What’s a vegetable garden without tomatoes? Sweet cherry tomatoes, giant beefsteaks, fleshy pastes … there’s a variety (or three) for every garden. Check out my post about common tomato plant problems and how to fix them.
Pests:
- aphids
- beet armyworm
- Colorado potato beetle
- cutworms
- flea beetles
- hornworms
- leafminers
- loopers
- stinkbugs
- thrips
- tomato fruit worm
- root knot nematode
- spider mites
Diseases:
- anthracnose
- black mold
- early blight
- fusarium wilt
- gray mold
- leaf mold
- septoria leaf spot
- target spot
- verticillium wilt
- bacterial canker
- bacterial speck
- bacterial spot
- bacterial wilt
- blossom-end rot
- catface
- edema
- fertilizer burn
- little leaf
- nutrient deficiency
- sunscald
- water stress
- zippering
- buckeye rot
- late blight
- tomato mosaic virus
- tomato spotted wilt
- tomato yellow leaf curl disease
- curly top
Zucchini pests and diseases
You may end up pawning off your bumper crop later in the summer, but you want to make sure you get some zucchini for stir-fries, soups, and zucchini bread in the first place!
Pests:
- aphids
- armyworms
- cabbage looper
- cucumber beetles
- cutworms
- flea beetles
- leaf miners
- squash bug
- squash vine borer
- stinkbugs
- thrips
Diseases:
- Alternaria leaf blight
- Alternaria leaf spot
- cercospora leaf spot
- downy mildew
- fusarium crown and foot rot
- gummy stem blight
- powdery mildew
- septoria leaf spot
- verticillium wilt
- angular leaf spot
- bacterial leaf spot
- bacterial wilt
- aster yellows
- blossom-end rot
- cucumber mosaic
- cucurbit yellow stunting disorder virus
- squash mosaic
- watermelon mosaic
- zucchini yellow mosaic
- phytophthora crown and root rot
Pests and Diseases in the Herb Garden
Although herbs, most of which have a pungent aroma, typically repel pests, they still suffer from a few pests and diseases of their own.
Basil pests and diseases
Italian basil pairs perfectly with tomatoes for sauce, while Thai basil adds flavor to curries and tea.
Pests:
- aphids
- cutworms
- loopers
- owlet moths
- underwings
- flea beetle
- grasshoppers
- Japanese beetle
- leaf miners
- root knot nematode
- slugs and snails (see what snails eat)
Diseases:
- cercospora leaf spot
- downy mildew
- fusarium wilt
- gray mold
- leaf spot
- root rot
Mint pests and diseases
Mint grows happily anywhere, providing you with plenty of leaves for refreshing iced tea (and potentially taking over), and it suffers from very few problems.
Pests:
- aphids
- cutworms
- spider mites
- thrips
Diseases:
- mint rust
Parsley pests and diseases
Whether flat or curly, the leaves of this biennial herb have a wide range of uses in the kitchen.
Pests:
- aphids
- armyworm
- cutworms
- root knot nematode
Diseases:
- Alternaria leaf blight
- cercospora leaf blight
- crater spot
- damping-off
- powdery mildew
- rust
- septoria leaf spot
- carrot motley dwarf
Rosemary pests and diseases
A shrubby herb, rosemary can even be grown as a hedge in mild climates or protected locations.
Pests:
- aphids
- leafhoppers
- spider mites
- spittlebugs
- thrips
- whiteflies
Diseases:
- cottony soft rot
- downy mildew
- crown gall
Pests and Diseases in the Flower Garden
Keep your flower garden healthy and beautiful by protecting your plants from — and, if necessary, treating them for — the pests and diseases that can damage them.
Rose pests and diseases
These classic, elegant blossoms come in a range of soft and vibrant colors, many with a sweet scent, and can find a home in almost any garden.
Pests:
- aphids
- Japanese beetles
- mites
- thrips
- rose scale
- rose leafhopper
- rose slugs
- leafcutting bees
Diseases:
- black spot
- powdery mildew
- stem canker and dieback
- rust
- Botrytis blight
- rose rosette disease
- rose mosaic
- crown gall
Peony pests and diseases
The large, ruffled blossoms of peonies brighten up the spring garden year after year, and these plants suffer few problems.
Pests:
- Japanese beetles
- scales
Diseases:
- Botrytis blight
- leaf blotch
Lavender pests and diseases
The soft green foliage and fragrant purple flower spikes of lavender fit in equally well in flower beds and herb gardens.
Pests:
- spittlebugs
- whiteflies
- aphids
- four-lined plant bug
Diseases:
- root rot
- crown rot
- alfalfa mosaic virus
- xylella
- shab
- Botrytis blight
- septoria leaf spot
Clematis pests and diseases
Beautiful flowering clematis vines rarely have problems with pests and diseases once well established.
Pests:
- aphids
- slugs
Diseases:
- clematis wilt
- clematis leaf spot
- powdery mildew
Sunflower pests and diseases
Large, cheery sunflowers brighten up vegetable garden borders, flower beds, and fence lines.
Pests:
- cutworms
- grasshoppers
- loopers
- painted lady caterpillar
- seed weevils
- silvery checkerspot caterpillar
- stem borers
- stem and root weevils
- sunflower beetle
- sunflower headclipping weevil
- sunflower moth
- sunflower bud moth
- sunflower root moth
- tumbling flower beetle
- wireworms
- woollybear caterpillars
Diseases:
- Alternaria leaf blight
- downy mildew
- Phoma blight
- powdery mildew
- septoria leaf spot
- verticillium wilt
When we learn to manage garden pests and diseases, our plants grow healthy, beautiful, and lush, and we can enjoy our gardens without worry.
Adriana Copaceanu is a passionate nature lover living in the country on her dream property where she grows vegetables, lavender, and wildflowers that she shares with the wildlife they attract. When she's not in the garden, she loves spending time with her chickens and planning her next nature project. Check out her books below:
How to Grow Lavender for Fun and Profit: Lessons Learned from Planting Three Hundred Lavender Plants
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