Solutions to 12 Common Fruit Problems

Get the scoop on common fruit tree problems—along with a few tips to make things right.
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©2012, Dorling Kindersley Limited

©2012, Dorling Kindersley Limited

©2011, Dorling Kindersley Limited

Photo By: Photo by Julie A. Martens

©2011, Dorling Kindersley Limited

©2011, Dorling Kindersley Limited

Photo By: Photo by Julie A. Martens

©2011, Dorling Kindersley Limited

Photo By: Photo by Julie A. Martens

©2011, Dorling Kindersley Limited

Photo By: Photo by Julie A. Martens

Photo By: Photo by Julie A. Martens

Photo By: Image courtesy of Minnesota Department of Natural Resources Archive, Minnesota Department of Natural Resources, Bugwood.org

An Apple A Day

Fruit trees are a garden investment that reward for years to come. Most fruit trees happily do their thing—flowering, setting fruit, thinning and ripening—with little input. Abandoned orchards bear witness to this. But fruit trees are susceptible to a host of pest and disease issues. Click through our gallery to diagnose your fruit tree problems—and learn some tips for solving these common issues.

Apple Scab Disease

Apple scab is a fungus disease that attacks apple leaves, stems and fruit. This disease is worst in areas with higher rainfall and humidity. In the Northeast, apple scab is so strong that commercial growers can’t produce a successful crop without treating for it. Planting resistant apple varieties and gathering fallen leaves helps control the disease. Fungicide sprays control apple scab, but must be applied at the right time. Check with your local extension service to learn the best way to treat apple scab in your region.

Peach Leaf Curl

Peach leaf curl is a fungus disease that attacks peach and nectarine trees. The leaves show the most common symptom of the disease: curled edges and deformed shapes. Ultimately, the disease can defoliate a tree and also damage fruit. Control the disease with one fungicide spray, either in spring before bud swell or in fall after 90 percent of leaves have fallen. Redhaven and its cultivars are more resistant to peach leaf curl.

Winter Moth Caterpillar

The winter moth is a non-native pest that attacks many different plants, including cherry, apple and crabapple trees. The adult moths mate during warm evenings in late fall and winter and lay eggs in tree bark crevices. The larva, an inchworm-like caterpillar, hatches in early spring and can quickly defoliate a tree. When you spot the caterpillars, spray Bt (Bacillus thuringinesis). When caterpillars eat this naturally occurring bacteria, they stop feeding and die. Use Bt early in the season and Spinosad, a natural pesticide option, after trees flower.

Codling Moth Caterpillar

The caterpillar form of the codling moth is the No. 1 pest of apple and pear trees, responsible for wormy fruit. The worms burrow into fruit anywhere, but typically attack where they have a little cover, like on the bottom end. Codling moth worms feed inside the fruit and eventually exit. The entry and exit holes are usually surrounded by brown, crumbly caterpillar poo. For control, use a mix of caterpillar traps and frequent sprays, either chemical or natural, such as kaolin clay or Spinosad, which is produced by soil microbes.

Protect Ripe Cherries

A family of robins and a few of their feathered friends can make quick work of your cherry crop. Protect your fruit by covering the tree with bird netting, which you can find online, at garden centers or in farm and feed stores. Drive bamboo poles into the ground around the tree and use twist ties to anchor the net to them. Or gather the net to the tree trunk beneath the leafy canopy and wrap twine around to hold it in place. When to net? As soon as fruits start to show ripe color—or whenever you see the first bird flying off with a cherry.

Peach Scab

Peach scab is a fungus disease that attacks peaches, nectarines and apricots. The fungus affects twigs, leaves and fruit, where it’s most noticeable. Proper pruning that allows good air flow into the tree helps manage the disease. The second key to control is fungicide sprays, which need to be applied from the time petals fall until about a month before harvest. Spray trees every 10 to 14 days.

Bitter Pit

Bitter pit attacks fruit trees worldwide—apple and pear trees are the types most affected. This disease is caused by a fungus and occurs most heavily in southern regions. Removing dead wood and any twigs with fire blight from affected trees helps with disease control. Gather and destroy any mummified fruit, which can contain the disease organism. The other key to control is fungicide sprays, which need to be applied from the time petals fall until harvest. Spray trees every 10 to 14 days.

Suckers

Fruit trees are notorious for producing suckers, stems that originate from the root system and are said to suck the life out of the tree because they don’t bear fruit. If your fruit tree is grafted, suckers grow from the rootstock, which is a different tree variety than the part that yields the fruit. To remove suckers, dig down to find the origin, and cut it cleanly. Clip a sucker at soil level, and next year two or more stems will appear at that same location.

Apple Sawfly Larva

The apple sawfly is a European pest that’s been infesting apple and crabapple fruit in New England since the 1940s. The larva burrows into fruit from the bottom, creating a visible—and unappetizing—trail. Infested fruit often aborts and doesn’t mature. It’s not uncommon for the larvae to munch their way through all the apples in a cluster. Treatment relies on pesticide applications, which must be carefully timed to avoid harming bees. Check with your local extension office for chemicals and timing.

Crown Gall on Apple Trunk

Crown galls, which are caused by a soil-dwelling bacteria, typically occur on apple, cherry, peach and plum trees. The bacteria usually infects the tree through a wound of some type. Galls start out small and can grow to enlarged sizes over time. Prevention is the best control method, because once the bacteria is in soil, it’s tough to eradicate it. If you have a tree with a gall, the bacteria can travel throughout the tree. Always sterilize pruning tools after working on the tree to avoid spreading the bacteria to other healthy trees.

Cherry Leaf Spot Disease

Cherry leaf spot is a disease caused by a fungus. It affects all types of cherries, although tart types usually show the greatest damage. The disease first appears as purple spots on leaves. Ultimately leaves die and the tree defoliates. The fungus overwinters on diseased leaves, so a vital step in controlling the disease is gathering fallen leaves and destroying them. Fungicide sprays also help keep the disease in check. Contact your local extension office for advice on spray types and timing.

Fire Blight

Fire blight is a bacterial disease that attacks apple, crabapple and pear trees. The disease occurs in many regions and is strongly present in the Mid-Atlantic. While it affects various parts of the tree, it’s best known for the way it makes leaves look like they’ve been burned. Treatment includes planting a resistant variety, avoiding high nitrogen fertilizers, and gathering and destroying fallen fruit, leaves and twigs. Copper and antibiotic sprays can also help control the disease. Check with your extension office for advice.