Pests and Diseases
Pests and diseases can have a far-reaching effect on vegetable crops. For the home gardener, they can be an inconvenience, but for commercial vegetable producers, they can be catastrophic.
Make use of Penn State Extension’s comprehensive library of resources including recommendations for managing pests and diseases for vegetables such as tomatoes, potatoes, onions, asparagus, squash, peppers, and many more. Find tips on dealing with worms, maggots, leaf miners, beetles, and mites, and scouting for pests. Penn State Extension also regularly publishes PestWatch Reports and Pennsylvania Vegetable Disease Updates in this section.
Common Vegetable Diseases
Vegetable diseases take their energy from the plants on which they thrive. Much the same as pests, diseases can be responsible for a great deal of damage. Wet weather, poor drainage, or inadequate airflow often encourages them. A variety of symptoms, including moldy coatings, wilting, blotches, scabs, rusts, and rot typically characterize plant diseases.
There are several common vegetable diseases that growers should be aware of. Timber rot, also known as Sclerotinia or white mold, can be a problem if air circulation and moisture retention are poor. Leaf mold can cause problems when you grow tomatoes in high tunnels. Early blight, caused by the fungus Alternaria solani, is a common problem for potato growers, particularly in warm weather regions that alternate between dry and wet.
There are distinct symptoms you can look for if you want to identify vegetable diseases. Penn State Extension’s Identifying Potato Diseases in Pennsylvania publication contains color photos to help determine what diseases are affecting your potato crops.
Preventative plant disease management tactics are the best approach to manage diseases. Basic principles include avoidance, exclusion, use of resistant varieties, accurate pathogen diagnosis, and pathogen reduction. Plant analysis plays a crucial role in determining what is wrong with your crops.
Scouting should be used to monitor your fields for the presence of diseases and pests or any potential issues that could hamper the growth of your vegetable crop. If your cucurbit crops are wilting, it could be cucurbit yellow vine decline, Fusarium, or bacterial wilt that is causing the problem.
Vegetable Garden Pests
Various insects and pests can damage vegetables in the garden and they can attack at all growth stages. The spotted lanternfly is an invasive insect that has been spreading throughout Pennsylvania for several years now.
Let’s not forget there are also lots of beneficial insects you can find in and around vegetable crops. Common natural enemies in high tunnels include green lacewings, lady beetles, and parasitoid wasps, all of which enjoy feasting on aphids, scales, and mites.
If you find white meandering tunnels in your chard, beet, or spinach leaves, your vegetables may be falling victim to leaf miners. The legless yellow to white larvae cause damage when they burrow between the layers of the leaves as they feed. Onion, seed corn, and cabbage maggots attack seeds and small seedlings.
Tomato hornworms can be a problem for tomato plants from July through early September in Pennsylvania. A single lime green, small shiny egg on the top or bottom surface of leaves of not only tomatoes but pepper and other solanaceous crops indicates their presence. Broad mites are another pest that can cause severe damage to peppers and tomatoes. You can protect your crops with an effective miticide.
Vegetable Crops and Integrated Pest Management
Integrated pest management (IPM) is a way you can manage insects, diseases, weeds, animals, and other pests that cause damage. It involves a combination of biological, cultural, mechanical, and chemical practices. You can apply the principles of IPM to both commercial and home vegetable growing. The key to applying integrated pest management is scouting for pests and diseases in vegetable crops.
Biological practices include releasing insects and mites along with bio-pesticides composed of specialized fungi and bacteria. Insect pheromone traps can also be used to help control insect pests such as black cutworm. Heat treatment of the soil is another practice that has a place in an integrated pest management system.
Vegetable Pesticide Application
There are several effective ways to deal with pests. If you want to use pesticides on your vegetable crops, you may need a license. You must fulfill a continuing education requirement if you want to maintain a valid private pesticide applicator license in Pennsylvania.
Penn State Extension provides a number of workshops for anyone who is looking to become certified or recertified. The courses available include the Private Pesticide Applicator Short Course in Spanish and English. A pesticide spray record-keeping spreadsheet is also available.
If you want to take the guesswork out of spraying there are smartphone and tablet apps you can use to help in sprayer calibration, nozzle selection, tank mixing, and product selection.
- News
2024 Late Blight Status Map
Date Posted 9/4/2024September 10, 2024 update of the late blight status in Pennsylvania and surrounding states. - News
2024 Cucurbit Downy Mildew Status Map
Date Posted 9/4/2024September 10, 2024 update of the cucurbit downy mildew status in Pennsylvania and surrounding states. - News
Dr. Heather Grab Joins Penn State Department of Entomology
Date Posted 8/22/2024The Vegetable, Small Fruit, and Pollinator Team welcomes new Entomology faculty, Dr. Heather Grab - News
A Comment Period Regarding Label Changes to Mancozeb is Open Until September
Date Posted 8/20/2024Mancozeb has been added to the pesticide review process and has a docket number. - News
Herbicide Contamination Discovered in Midash Forte
Date Posted 8/8/2024Penn State Extension has been notified of herbicide contamination in a lot of Midash Forte (Sharda USA, LLC) insecticide. Growers applying this product should suspend use until confirmed to be uncontaminated. - News
Phytophthora Infection Reported in Cucurbit Crops
Date Posted 8/6/2024Despite warm and dry soils this summer, intermittent storms allow for Phytophthora infection in central Pennsylvania cucurbit fields. - Articles
Tomato-Potato Late Blight in the Home Garden
This article describes tomato-potato late blight, including symptoms; disease development, cycle, and management; and management after harvest. - News
2024 Current Issues for PA Vegetable and Berry Crops: June 13
Date Posted 6/13/2024In general, seasonable temperatures and little precipitation across much of the state have dried out soil conditions from a wetter-than-normal spring. - Articles
Sap Beetle Injury in Sweet Corn Becoming More Prevalent in PA
A roadside stand operator in my area routinely traveled to eastern Pennsylvania to purchase bulk bins of sweet corn for sale at his market. - Articles
Particle Films as a Deterrent for Insect Pests
For the past 90 years, growers have utilized particle films to deter insect and mite feeding on horticultural crops. - Articles
Alternative Chemistries for Managing Corn Earworm in Sweet Corn
Growers have heard vegetable entomologists discuss the gradual loss of synthetic pyrethroids' efficacy against corn earworm in the Mid-Atlantic region. - Articles
Beware: Insufficient Financial Analysis and Misinformation Could Spell Trouble for Farmers' Finances
For growers, late fall and early winter is the time to recharge personal batteries, develop cropping plans for the next year, or attend educational meetings to expand knowledge. - News
Spotted Wing Drosophila: Early Damage Potential in 2024
Date Posted 6/6/2024Spotted wing drosophila (SWD) is being caught in monitoring traps in PA earlier than usual this year. - Articles
Flea Beetle Management in Cole Crops
Diminutive but destructive are two terms that describe flea beetles with respect to cole crop production systems. - Articles
Deterring Striped Cucumber Beetles in Organic Cucurbit Production Systems
Striped cucumber beetles overwinter as adults in crop debris and become active in the spring as soon as cucurbit crops are planted in the field. - Articles
Protect Potato Yields by Managing Colorado Potato Beetles
Colorado potato beetles are perhaps the most common and potentially destructive potato pest in the U.S. - Articles
Cercospora Leaf Spot on Table Beets
Growing up in Maryland, pickled red beets were a staple at every family dinner gathering. - Articles
Managing Alternaria Leaf Blight on Cantaloupe
While Alternaria leaf blight can infect other cucurbit crops like cucumber, watermelon, and squash, it tends to be more virulent on cantaloupes than on other cucurbits. - News
2024 Current Issues for PA Vegetable and Berry Crops: May 30
Date Posted 5/30/2024Almost all areas of Pennsylvania have received higher-than-average rainfall in the last few weeks. - Articles
Black Rot in Cole Crops
Black rot is one of the world's most economically significant diseases of cole crops. - News
Northeast Arugula Team Looking for Grower Assistance
Date Posted 5/29/2024Researchers at Penn State are asking growers for help identifying bacterial diseases of arugula and other brassica leafy greens in Pennsylvania vegetable production systems. - Articles
Invasive Insect: Thrips parvispinus
Thrips parvispinus is an invasive insect that can cause significant damage to various plants and agricultural crops. - Articles
What About Biopesticides?
Resistance issues, government bans, and supply chain issues can make finding the right spray daunting. - News
2024 Current Issues for PA Vegetable and Berry Crops: May 16
Date Posted 5/16/2024A cool, wet start to the growing season has made it difficult to access fields this year.