- Author: Nick Volesky, Utah State University Vegetable IPM Associate
- Posted by: Elaine Lander
- Blossom drop occurs when daytime temperatures exceed 90°F and nighttime temperatures stay above 72°F for several days, causing tomato pollen to become nonviable and blossoms to dry out and drop without producing fruit. Blossom drop can also occur if there is no pollination or temperatures dip below 55°F at night. It can be prevented by setting up shade cloth to protect plants during the hottest periods of the growing season.
- Blossom end rot is the death of tissue on the blossom end of tomato fruits, appearing as dark brown-black target-like rings. It occurs when plants are unable to move enough calcium from the soil throughout the plant, with the tomato being the farthest location and thus getting the least calcium. Blossom end rot can be prevented by evening out the watering to allow the plant to continually uptake water and calcium. Consider using mulch around the plants to prevent water loss.
- Cat-facing is when tomatoes are distorted and misshapen. The damage is caused by one of many factors such as blossom scarring, high nitrogen levels, temperature fluctuations, excessive pruning, or insect feeding. Avoid “cat-faced” fruit by growing cultivars that are less prone to cat-facing (heirloom varieties tend to be more prone). Provide adequate growing conditions and good pest management.
- Cracking and splitting on tomatoes occur when there are rapid changes in soil moisture levels which can cause the fruit to expand quicker than its skin can grow. Openings can leave fruit susceptible to insects and diseases. Prevent this by providing plants with an even watering schedule.
- Cold or freeze damage occurs when tomato plants are exposed to temperatures below 35°F, where plant cells expand, freeze, and die, causing interveinal spots. Leaves on established plants may turn purple and dark. After transplanting, follow weather forecasts closely in the spring and cover plants to protect from any expected frosts.
- Green shoulders appear when tomato fruits are fully ripening, but the top “shoulder” ends remain green and yellow. This is simply caused by genetics and environmental conditions (high temperatures and exposure to direct sunlight).
- Herbicide damage occurs when an broadleaf herbicide contacts the plant directly or indirectly via drift or vapors. Some herbicides that are sprayed in hot temperatures can volatilize and move as a vapor for long distances, affecting vegetable crops. Herbicide damage symptoms include small misshaped leaves that are thick and tightly curled.
- Horn/nose Development is a physiological and genetic disorder. A few cells divide abnormally and the fruit produces an extra locule (interior segment within the tomato). This mutation often occurs in very cool or very hot temperatures during tomato fruiting.
- Edema/oedema is a physiological disorder identified by watery blisters or swellings that form along the leaf veins. It is induced by high relative humidity and light quality. Because of this, edema is most commonly observed in enclosed settings such as greenhouses.
- Leaf curling is associated with various environmental stresses, viral infection, or herbicide damage. Environmental stresses include excessive moisture and nitrogen, heat, drought, severe, pruning, and transplant shock.
Leaf curling on tomato
(Credit: M Murray, USU Extension IPM Program) - Sunscald on tomatoes begins as yellow/brown discoloration on the sun-exposed side of the fruit. Eventually, the flesh becomes tough, white, and leathery. This damage exposes the tomato to potential rot pathogens.
- Zippering is an abiotic condition that occurs when the flower anther sticks to the developing fruit as it grows. Symptoms include a thin brown longitudinal scar (with transverse scars) extending down the fruit, resembling a zipper. Zippered fruits that are intact are still edible; however, openings that ensue can allow pathogen infections or further insect damage.
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For more on pests and disorders of tomato, see our website for information on managing pests of tomato and horticultural tips for growing tomato.
You can also register for our upcoming webinar on plant diseases Thursday, July 15 at 1:00pm PDT. Attendance is free and open to the public but registration is required. See Urban & Community IPM webinar website for more details.
- Author: Belinda J. Messenger-Sikes
Figuring out what's wrong with your plant takes a little detective work. Plants can look unhealthy for a number of reasons, including diseases, pest insects, or even environmental conditions like sunburn, too much water, not enough water, wind damage, and other issues. Start by examining the plant closely for anything out of place. Knowing what the plant should look like will help you determine if there's a problem. Because some pests attack only specific plants, identifying the type of plant, including the variety or cultivar, narrows down disease possibilities.
Diseases caused by a plant pathogen, like a fungus, will look and act differently than something caused by environmental factors. Note the plant's location in the garden or landscape and compare the symptoms to nearby plants. Disease symptoms will usually develop slowly and unevenly on one type of plant. Damage from environmental issues is more likely to appear quickly and be widespread.
If the plant is growing in a preferred location and receiving the right amount of water and fertilizer, it will be less susceptible to disease and environmental disorders.
To learn more about plant diseases and what might be affecting your plant, find your plant in the UC IPM plant disease index. Not sure if you have a disease or another type of pest? Use the plant problem diagnostic tool to help narrow down what's wrong with your plant. Find out more about plant problems on the UC IPM website.
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- Author: Elaine Lander
With the recent time change along with a change in temperatures, landscaping practices for pests need some adjusting too. We're sharing a few recommended tasks to help prevent insect pests, diseases, and environmental disorders in landscapes. Looking for additional tips? You can subscribe to our Seasonal Landscape IPM Checklist for monthly landscaping reminders delivered straight to your email inbox.
Frost Protection
Irrigation
Adjusting water schedules is an important part of integrated pest management. Different plants have different watering needs and too much or too little water can damage or kill plants. Reduce irrigation frequency or turn off automated systems if rainfall is adequate or irrigate deeply if the weather is dry. Learn more about irrigating fruit and shade trees and shrubs on our website.
Prune
Deciduous trees and shrubs such as apple, crape myrtle, pear, and peach need to be pruned to maintain their structure and health. Proper pruning can also help manage and prevent certain pests. Our website has plant-specific pruning information for a number of fruit, nut, and landscape trees. Be sure to remove dead, diseased, and borer-infested wood.
Sanitation
Now is the time to clean up old fruit and nuts under trees to avoid harboring pests. Removing fallen leaves from beneath fruit trees and roses will also help reduce insect and disease problems. This practice of sanitation is a key component of integrated pest management to prevent and reduce pests. See our website for additional sanitation tips in your landscapes and gardens.
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Winter is an ideal time to prune deciduous fruit and shade trees, since the trees are dormant and you can more easily see the tree canopy. In many cases, pruning can also help prevent or control certain insect and disease problems.
For help with pruning, visit the UC IPM web page called Pruning fruit and shade trees and shrubs.This page provides links to plant-specific pruning information for fruit trees, nut trees, landscape trees, and others. You can also find links to diseases and environmental disorders that commonly affect fruit and shade trees, as well as additional information on the topics of landscape management and videos on how to train young trees.
It's important to note that while pruning many types of fruit trees in winter is advised, you'll want to wait until summer to prune apricot and cherry trees. Read Avoid Pruning Apricots and Cherries in Cool Season to find out why.
Pine trees do best when planted in well-drained soil in full sun, and most species need little water once established. Trees can ward off attacks by many insects and diseases if taken care of properly.
Several diseases can affect pine trees, such as rusts, blight, and root rot. Disease symptoms vary, but may include discoloration of leaves or needles, cankers, galls, and ooze.
Pine trees are susceptible to damage by over 20 different kinds of insects, including aphids, borers, caterpillars, mealybugs, and weevils. Look for signs of insects by examining needles, branches, and bark. To learn about some of the various beetles attacking trees and devastating pine forests, read the article Pines, Drought and Beetles.
When your pine tree looks unhealthy but you can't find any traces of an insect pest or disease, a possible cause is an environmental disorder. These include drought, frost, mineral deficiencies and excesses, and others. Environmental, or abiotic, disorders can be difficult to diagnose.
See a larger list of diseases, insects, and environmental disorders that affect pines by visiting the Pests in Gardens and Landscapes: Pine web page. For help diagnosing a problem, contact your local UC Master Gardener office.
You can also read about tree deaths caused by the drought and other factors as well as how to keep your trees healthy by visiting the UC ANR Forest Research and Outreach page on Tree Mortality.
