Fruit

Pests and Diseases

Fruit diseases and pests are extremely common, making the use of chemical controls an important part of the production process. On this page, fruit growers will find information and tips on managing diseases, fruit bugs, and insect pests on crops such as apples, pears, grapes, and berries. Advice on using fungicides, antibiotics, insecticides, and miticides can be found, as well.

Common Fruit Diseases

Fruits crops, like all other plants, are susceptible to various diseases that can cause adverse changes and affect production. Scab, for example, is among the most common pear and apple diseases.

Apple scab is caused by a fungus and early infection signs can be spotted on the leaves, stem, or blossom end of the fruit. Lesions manifest in dull, olive green areas or spots. To prevent secondary infections, it’s critical to scout and control apple scab early in the season.

Pear scab has very similar symptoms and disease cycles. Unlike apple scab, however, pear scab frequently appears on twigs, where it can survive during winter and start new infections in spring.

Gray mold is another prevalent cause of disease in apples and pears. The primary infection points for the introduction of gray mold are fruit injuries and wounds. The disease can easily spread from infected to adjacent healthy fruit in storage.

Penn State Extension offers in-depth information on a number of fruit tree diseases, including strawberry leaf spots and leather rot, wooly apple aphid, and phytophthora root rot in raspberries. Resources on common stone fruit and plum tree diseases are also available.

Tree Fruit Insect Pests

Fruit pests can cause a significant decrease in yield. One of the more devastating fruit tree pests is the spotted lanternfly. It is an invasive insect that feeds on a wide range of plants. Penn State Extension provides growers with Spotted Lanternfly Management Resources, as well as permit training and best practices to stop its spread.

Other common fruit tree pests include American plum borer, dogwood borer, and oriental fruit moth. Additionally, tree fruits can be attacked by various species of plant and stink bugs.

Orchard Integrated Pest Management

Integrated Pest Management, or IPM, allows fruit producers to ensure proper pest management decisions that are economically, environmentally, and socially sound. IPM begins with collecting detailed information about a crop and its pest, also known as scouting.

Regular field scouting is key to conserving soil and reducing pesticide use. Along with scouting, implementing IPM insect monitoring can be a cost-effective way to detect the presence of pests in traps placed in orchards.

For further information on orchard IPM, access the Field Guide to Tree Fruit Disorders, Pests, and Beneficials. The publication – available in both English and Spanish – can be beneficial to orchard employees, who are often the first to detect a fruit disease or insect pest.

Fruit Fungicide and Pesticide Application

Fungi-caused infections are one of the most prevalent orchard diseases. They are often managed with either fungicidal or fungistatic pesticides. Fungicides are separated into two categories: protectants and systemics.

Protectant fungicides are designed to protect plants against infections at the application site. Systemics prevent diseases from developing on parts of the plant away from the application site. Discover more with Penn State Extension’s resources on fungicide resistance, proper usage and maintenance, and fungicide recommendations for apple diseases.

Fruit growers can find guidance and tools for spray products usage, such as the Spray Record-Keeping spreadsheet. Advice on apple insect and mite control is also available, as well as certification training for private pesticide application.

View as List Grid

Items 1-25 of 198

Sort by:
Date Posted Set Ascending Direction
  1. Blueberry Growers Twilight
    Workshops

    Free

    Blueberry Growers Twilight
    When 04/05/2024
    Length 2 hours
    Refine blueberry cultivation with pruning, soil nutrition, and disease insights. Penn State experts share strategies for success. Ideal for all growers.
  2. If not already completed, dormant fungicides need to be applied as soon as possible on peach and nectarine trees to limit peach leaf curl infection. Photo: K. Peter, Penn State
    News
    2024 Disease Update: Dormant Copper Sprays and Orchard Sanitation
    Date Posted 3/4/2024
    Early season disease management for the 2024 season should be underway. Consider dormant applications of copper to manage fungal and bacterial diseases on fruit trees. Sanitation is critical for limiting fruit rots in the orchard.
  3. The disease first emerges on upper sides of leaves as tiny, red to purple, circular spots. After the leaves become infected, they turn yellow and fall. Photo by K. Peter.
    Articles
    Cherry Disease - Cherry Leaf Spot
    Cherry leaf spot, caused by the fungus Blumeriella jaapii (formerly Coccomyces hiemali), attacks the leaves, leaf stems, fruit, and fruit stems of tart, sweet, and English Morello cherries.
  4. The aphids’ bodies are nearly covered by a woolly mass of long waxy fibers that gives them a whitish, mealy appearance and that are much shorter on the root-inhabiting aphids. Photo by G. Krawczyk.
    Articles
    Tree Fruit Insect Pest - Woolly Apple Aphid
    By Grzegorz (Greg) Krawczyk, Ph.D.
    The woolly apple aphid, Eriosoma lanigerum, is a widely distributed pest of apple trees, especially where its parasites have been killed by insecticides.
  5. On leaves of new shoot growth symptoms of powdery mildew are feltlike, white patches on the margins and lower surfaces. Infected leaves curl upward and soon become covered with a powdery coating of spores. Photo by K. Peter.
    Articles
    Apple Disease - Powdery Mildew
    By Kari A. Peter, Ph.D.
    Powdery mildew, caused by the fungus Podosphaera leucotricha, attacks buds, blossoms, leaves, new shoots, and fruit of wild and cultivated apples and crabapples.
  6. The fungi enter the developing fruit through an opening in the calyx. Photo by K. Peter.
    Articles
    Apple Disease: Moldy Core
    By Kari A. Peter, Ph.D.
    Moldy core is caused by several different fungal pathogens. Many cultivars of apples are affected, including Delicious, which is very susceptible.
  7. Source: Keren Levy, Bugwood.org
    Articles
    Apple Disease - Core Rot
    By Kari A. Peter, Ph.D.
    Core rots are caused by various fungi. The most susceptible cultivars are Delicious, Golden Delicious, Gravenstein, and Idared, which all have an open sinus extending from the calyx into the core region.
  8. Tree Fruit Production Guide
    Guides and Publications

    Starting at $15.00

    Tree Fruit Production Guide
    By Kari A. Peter, Ph.D., Grzegorz (Greg) Krawczyk, Ph.D., Rob Crassweller, Ph.D.
    Get the most up-to-date information on growing tree fruit on a commercial scale. Revised information and a refreshed look for 2024.
  9. Environmental Protection Agency Mitigation Proposal Update:  Ziram/Thiram/Ferbam
    News
    Environmental Protection Agency Mitigation Proposal Update: Ziram/Thiram/Ferbam
    Date Posted 12/12/2023
    The first week in December 2023, the EPA hosted a webinar to address concerns and outline new measures for mitigating risks pertaining to using three commonly used fungicides: ziram, thiram, and ferbam.
  10. Sources Of Plant Disease In Greenhouses
    Articles
    Sources Of Plant Disease In Greenhouses
    By Gary W. Moorman, Ph.D.
    Where do diseases begin? It is important to prevent losses due to plant pathogens by reducing or eliminating the numbers of pathogens at their source.
  11. Adult beetles are ¼ inch long, dark brown with whitish patches, with four humps on their wing covers, and a protruding snout one-third its body length. Photo by G. Krawczyk.
    Articles
    Tree Fruit Insect Pest - Plum Curculio
    By Grzegorz (Greg) Krawczyk, Ph.D.
    Plum curculio, Conotrachelus nenuphar, is an injurious pest of apples, cherries, nectarines, peaches, and plums throughout the state.
  12. Source: Whitney Cranshaw, Colorado State University, Bugwood.org
    Articles
    Tree Fruit Insect Pest - Rose Leafhopper
    By Grzegorz (Greg) Krawczyk, Ph.D.
    Rose leafhopper, Edwardsiana rosae, is a minor pest on apples in the Mid-Atlantic region. Orchards in the vicinity of multiflora rose or brambles are especially at risk.
  13. Scales on new growth and fruit produce deep purplish-red coloration in the tissue. Photo by G. Krawczyk.
    Articles
    Tree Fruit Insect Pest - San Jose Scale
    By Grzegorz (Greg) Krawczyk, Ph.D.
    The San Jose scale, Quadraspidiotus perniciosus, is a pest of fruit trees, but it attacks many other trees as well as shrubs.
  14. Source: Natasha Wright, Cook's Pest Control, Bugwood.org
    Articles
    Tree Fruit Insect Pest - Shothole Borer
    By Grzegorz (Greg) Krawczyk, Ph.D.
    The shothole borer, Scolytus rugulosus, sometimes called the fruit tree bark beetle, is a native of Europe but now occurs throughout the United States.
  15. Source: Ben Sale, available under creative commons license 2.0 creativecommons.org/licenses/by/2.0/legalcode
    Articles
    Tree Fruit Insect Pest - Spotted Tentiform Leafminer
    By Grzegorz (Greg) Krawczyk, Ph.D.
    The spotted tentiform leafminer, Phyllonorycter blancardella, affects the leaves of apple trees throughout the growing season.
  16. Source: Todd M. Gilligan and Marc E. Epstein, CSU, Bugwood.org
    Articles
    Tree Fruit Insect Pest - Variegated Leafroller
    By Grzegorz (Greg) Krawczyk, Ph.D.
    Although variegated leafroller, Platynota flavedana, is an important pest of apple in Virginia and West Virginia, it only occasionally causes damage in southern Pennsylvania.
  17. Source: Frank Peairs, Colorado State University, Bugwood.org
    Articles
    Tree Fruit Insect Pest - Western Flower Thrips
    By Grzegorz (Greg) Krawczyk, Ph.D.
    Widespread fruit loss from western flower thrips, Frankliniella occidentalis, was first observed in early 1990.
  18. Leafhopper nymphs are whitish green, smaller, and wingless, and are usually found on the undersides of older leaves.  Photo by G. Krawczyk.
    Articles
    Tree Fruit Insect Pest - White Apple Leafhopper
    By Grzegorz (Greg) Krawczyk, Ph.D.
    White apple leafhopper, Typhlocyba pomaria, was abundant in many apple orchards throughout the state until the introduction of the neonicotinoids about 10 years ago.
  19. The tufted apple bud moth is named for the tufted scales that can be seen as two or three groups on the tops of the wings. Photo by G. Krawczyk.
    Articles
    Tree Fruit Insect Pest -Tufted Apple Bud Moth
    By Grzegorz (Greg) Krawczyk, Ph.D.
    The tufted apple bud moth, Platynota idaeusalis, is a serious direct pest of apples in the five-state Cumberland-Shenandoah region of the eastern United States.
Page
You're currently reading page 1