As we try to prevent pests through City Fruit’s Save Seattle’s Apples campaign, we want to take a step back and look at what those pests really are. In the Seattle area, apple maggot and coddling moth are Public Enemy One and Two. Both do their damage to the fruits themselves, while leaving the tree itself relatively unharmed. The type of damage each one causes is very distinct and can be easily identfified. After you’ve learned to tell them apart, you can also prevent them both in one foul swoop!
Since first being detected in Portland in 1979, apple maggot, Rhagoletis pomonella, has been one of the most destructive pests in the Northwest. While they were named after the fruit they are most commonly associated with, apple maggots can also be found in plums, pears, and cherries. Adult apple maggots, or fruit flies, lay their egs inside of the host fruit. The laying of the egg just inside the apple’s skin gives an infested apple skin small dimples. When the larvae hatch, they crawl throughout the apple, leaving small brown-tunnel mazes in their tracks. When mature larvea exit the apple, they crawl to the ground and overwinter in the soil, developing into mature fruit flies the following year. Apple maggot flies first emerge in late spring and continue throughout the summer.
Ubiquitous around the globe in temperate climates, coddling moth, Cydia pomonella, has been the most damanging apple (as well as pear pest) for the past 200 years. Coddling moth eggs are generally laid on leaves or directly onto fruit. When first laid, they are almost comptelely transparent, which makes them very difficult to see. Unlike most larvae in the family, coddlingmoth feed on flesh in the center of the apple as well as the seeds. An apple damaged by coddling moth tends to have a single deep hole burrowed to the center of the apple, as opposed to the many small tunnels throughout the apple’s flesh from maggot damage.
Stopping the Madness: Protecting Your Fruit
While the most common form of protection throughout the years has been pesticides such as Diazinon, many places have begun banning these types of sprays due to environmental and health risks. City Fruit advocates and encourages protective methods that do not pose harm to the tree and its ecosystem. The three types of organic methods that City Fruit reccommends all involve placing an actual physical barrier over the fruit to prevent pests from causing damage. These three methods are: bagging apples, placing footies with kaolin clay on each piece of fruit, or netting the entire tree.
“Bagging fruit” means placing a physical bag over each piece of fruit on a tree. These baggies should be compostable and have a thin, waxy covering in order to wick off rain. Before the fruitbecomes a quarter-sized, thin each fruit cluster down to one apple, place a baggie over the fruit, and secure it with a twist tie. The piece of fruit will grow in a completely normal fashion in the bag, but may have a slighlty lighter color than normal due to its limited exposure to sunlight. City Fruit is providing these baggies for free at various partnering locations throughout the city! Check out the locaiton nearest you.
Footies and Kaolin Clay
Footies are a nylon knit wrap that goes over invididual pieces of fruit just as the baggies do. Footies should also be used with a twist tie to secure them to the fruit at the stem. Kaolin clay is a safe, naturally occuring clay substance found in soil. While footies can be used on their own, making a water/clay mix to dip the footies in before wrapping has shown a higher rate of success. Kaolin clay both masks the color of the fruit (making it less appealing to pests) and the smell (masking the location of the fruit.) City Fruit is also providing a kaolin clay mix at our office in South Lake Union. Check out the available pick-up times here.
The most all-encompassing form of pest prevention is netting. Netting can be done to an entire tree or just to a portion of the tree (often done for very large trees.) Special netting can be purchased and placed over a tree (and then secured to the bottom of the trunk) that prevents pests from getting to the tree. Netting is a great, time-efficient way of protecting an entire tree wherecovering individual pieces of fruit is not possible. For tree owners intersted in netting, City Fruit is providing netting, as well as the personpower (if desired) to cover trees through the Tree Care Services program.