Five Useful Organic Pesticides for Fruit Trees
Five Useful Organic Pesticides for Fruit Trees
Almost everyone who grows even just a little fruit wants to use as few chemicals as possible; many of our customers are interested in growing fruit trees organically. We’ve experimented with number products over the years, and here are a few organic solutions for fruit trees that really work:
1) Bacillus thuringiensis (Bt) is a favorite of ours. It is very effective at controlling problem moths and caterpillars if used property. Bt is a naturally-occurring bacteria that causes insects that have a caterpillar larval stage to become ill and die. It only works on certain moth and butterfly species; it is not harmful to other insects. It usually comes in a liquid or powder form. Bt is a an actual living organism, so it doesn’t have a long shelf life. To control an infestation of caterpillars, including peach twig borer, apply Bt over the entire tree – trunk, leaves, and branches – once when the tree is blooming and again when the petals fall. There is another variety of Bt called Bacillus thuringiensis israelensis that kills mosquito larvae if added to standing water where mosquito larvae grow.
2) Copper fungicide is an essential component to any pest control program for fruit trees. Most modern fruit tree cultivars are very susceptible to fungal diseases. A handful of varieties are resistant to certain diseases, but as a general rule, the gardener or orchard grower has to control fungal diseases with a spray program. Copper fungicides are an organic solution for fungal disease, but don’t be surprised if you see them listed as a conventional pesticide as well. Copper fungicides work by inhibiting the ability of certain microorganisms to feed on plants. This prevents the disease from harming the plant and breaks the disease cycle. Apply copper fungicides to plants that show signs of disease and continue spraying every 7-14 days as long as the disease persists, up until the day of harvest. Copper fungicides can even be used to control fireblight on apples and pears.
3) Soap, including homemade concoctions and pre-mixed insecticidal soaps, are an effect organic insecticide for many fruit tree pests. The soap is especially effective on smaller insects; grasshoppers may not stay still long enough to receive a lethal dose. The soap kills insects by disrupting their cellular membranes, and it may also remove the waxy protective coating of an insect. Soap has been used as an insecticide for over 200 years. If mixed properly, it will not harm the tree and it can be used up until the day of harvest. To make your own insect-killing soap concoction, add 1-2 tablespoons of liquid soap (NOT DETERGENT) to one quart of water in a spray bottle or garden pump sprayer. Some gardeners have also added chopped garden-grown hot peppers or garlic to the mixture for a more intense spray. Smaller insect pests will be killed by a homemade soap spray.
4) Neem oil is a highly-effective pesticide that serves as a miticide, fungicide, and insecticide. Neem oil works as a miticide, killing smaller soft-bodied insects by smothering them. It works as a fungicide by killing existing fungal infections and coating the leaf to prevent additional infections. It works as an insecticide by smothering larger insect pests if infestations of such pests are not severe. Neem oil should be applied to the entire plant when the plant is not in bloom, as the oil can prevent flowers from pollinating. Neem oil may also kill honeybees if it is applied when bees are present on the plant. After application, neem oil acts as a repellent to insect pests. The neem oil itself is a natural oil found in an evergreen tree native to India.
5) Spinosad is a newer biological pesticide that is created from a chemical compound found in a species of soil bacteria. It kills and disrupts the lifecycles of numerous insects. It is non-toxic to mammals and beneficial insects. It is applied to leaves and when leaves or plant material are consumed by insects, such as grasshoppers, the spinosad acts on the insect neural system, killing them. It also kills some insect pests on contact. It has virtually no residual effect – it must be consumed or sprayed directly on an insect pest. Spinosad also controls the larval stage of insect pests that are targeted by Bt. Apply spinosad every 5-7 days until the pest is no longer a problem.
So there are five extremely useful organic pesticides. What have you used as an effective organic method for insect and disease control? Let us know in the comments!
I’m planning a blog post in the near future for homemade organic pesticides…Thanks for reading!