Vegetables and Fruit Crops Study at the University of Florida: Diseases and Pests of Fruit

November 19, 2012

A pest is any organism that negatively directly or indirectly affects fruit quality either pre- or post-harvest. Pests that attack fruit crops include bacteria, mollicutes: (Bacteria without cell wall, phytoplasmas), fungi, insects, weeds, and nematodes.

Then we have bacterial diseases that can cause damage to fruit, leaves, and stems. They spread by tools, wind, rain, and labor. They can be control with genetic resistance, chemical sprays, which may not be very effective, and sanitation.

Bacterial Diseases and the Fruits they affect:

Fireblight – apples, pears
Citrus canker, greening -oranges, grapefruit
Bacterial canker – peaches
Bacterial Leaf Spot
Crown gall - apples, peaches, cherry, grapes

Fungal Diseases can affect leaves, fruit, stems, and roots. They spread by soil and aerial means (rain). They can be control with genetic resistance, fungicides, and biological ways (natural).

Important Fungal Diseases and the Fruits they affect:

Black sigatoka – banana
Fusarium, many crops – bananas
Brown rot – peaches, citrus
Black rot/ripe rot (postharvest) – grapes
Scab – apple, citrus, peach
Powdery mildew (dry environment) – grapes, apples, chestnut, cherries
Wilt – grapes, blackberries, raspberries
Anthracnose – avocado, mango

Mollicutes are similar to bacteria, lack cell walls, and survive on inorganic sources. They have a life-like similar to bacteria, and decline symptoms similar to viruses.

Important Mollicute Diseases and the Fruits they affect:

Witches Broom – Limes
Stubborn Disease (spiroplasma) – Oranges
Pear decline
Lethal Yellows (phytoplasma) – Coconut
Grapevine Yellows

Virus Diseases are the most severe of all diseases. They spread by budwood, budding, grafting, insects, mites, nematodes, and pollen. They can be control with genetic resistance and heat therapy.