On a chilly fall morning, over 35 participants gathered to discuss integrating nature’s services into apple production at Luz del Valle Farm in Corralitos, CA. The operation showcases a diverse farmscape that offers numerous niches for beneficial organisms. Stewardship is front and center on this farm.
Beneficial species at Luz del Valle Farm — Karell Reader (Luz del Valle Farm) discussed beneficial insects, bats, birds and snakes on the farm which help with pest control. She and her husband Phil support wildlife in five areas on the farm with native plants that are good for cover, for food sources, and for nesting sites. They also leave vegetation on the orchard floor, instead of tilling, to provide additional habitat for natural enemy insects. She said that one important factor in their pest management strategy is the decision to tolerate a certain amount of crop damage. They try to limit it as much as they can, but recognize that if you do a complete kill, for instance of all the aphids, then there's nothing left for the ladybugs to consume. She wants to keep the beneficials around and happy, so they are ready to help whenever they are needed.
Beneficial Insect and Bird Pest Control of Codling Moths — Jo Ann Baumgartner (WFA) shared how flowers of native and nonnative plants in apple orchards support beneficial insects like hoverflies and parasitoid wasps which can help reduce rosy apple aphid and codling moth pests. Flower diets from coriander, wild carrot, annual buckwheat and parsnip can increase longevity and parasitism capacity of parasitoid wasps. Ground covers can decrease pest insect abundance in general. Birds also help with pest control, as seen in Jo Ann’s research where 81% of the live overwintering experimental codling moths in apple orchards were eaten by birds. With Sacha Heath’s research, she found 35% of the codling moths in walnut orchards were consumed by birds.
Habitat and Cultural Practices Reduces Pesticides — Terence Welch (Welch Consulting) described organic apple orchards where the application of Bacillus thuringiensis (BT) for leafrollers was stopped once tilling was changed to every other row, every other year while incorporating a cover crop. Nine species of cover crops were used to increase the diversity of beneficial insects, and the variety of soil life without increasing nitrogen levels. Alternating tillage and cover crops helped to maintain yields and keeping the N down dramatically discouraged fire blight. Two dormant horticultural oil sprays were used to smoother rosy apple aphid eggs – one in January – and the other at 1/4 inch bud break. While lady beetles are the ultimate aphid control when they arrive later in the spring, solider beetles and hoover flies are also important. Pheromones were used to disrupt codling moth mating, but birds also help to control the overwintering pupae. Suggestions for scouting included checking 100 terminals of new growth in each apple block twice a week by not just looking for pest damage, but also by touching the plant to feel if it's sticky or pests are present.
Lessons Learned about Pest Management in Apples — Bill Denevan (Viva Tierra) shared organic techniques for replanting an orchard that died from phytophthora by using 8 lbs of mustard meal in the planting hole one month or so before planting and choosing a special root stock resistant to the disease. For all insect pests, he stressed the importance of knowing what the pest pressure is from the surrounding agriculture. For example, if there is an adjacent organic raspberry field, it could be a source of leafrollers; or if an adjacent apple orchard with high codling moth numbers, the use of pheromones sometimes is not enough. He shared that mating disruption (pheromones) only works if there's at least one acre of apples. If the codling moth population is high, pheromones and oil sprays may both be necessary. This area has three generations of codling moth per year, so the idea is to control them during the first generation.
Barn Owls for Natural Rodent Control — Rebecca Dmytryk (Humane Wildlife Control Inc.) presented on the benefits of providing nest boxes to attract Barn Owls for natural rodent control. She made the case for the need of an overall nest box size of 10 ft3 by showing videos of the birds in boxes much smaller, where they are not able to spread their wings or stand upright. She also shared the size and placement of the entry hole, and other critical components and considerations that impact the welfare of the owls and their breeding success.