- Author: Trina Tobey
They plague every gardener's nightmares. Like something from a sci-fi movie, they are green with long legs and antennae and long piercing mouths with which they suck out fluids. They eat 100 times their body weight, and—worst of all—they multiply asexually by the dozens in a day!
My first experience with aphids as a beginning gardener was watching the leaves on my plum tree wilt. The flowers fell off and died instead of producing fruit. This prompted me to research what I could do to protect my fruit trees. Here is what I learned.
In fall it is time to start your preventative measures for aphids on fruit trees for next year. After harvest, a zinc sulfate application on plums and prunes will provide zinc to the trees as well as hasten leaf fall disrupting the aphid life cycle.
If aphids are a chronic problem in your fruit trees, you can apply supreme- or superior-type oils to kill overwintering pests during dormancy this winter. This helps to start the following season with a clean slate.
In the spring, start monitoring your trees for aphids as soon as leaves begin to bud. Check for aphids on the underside of the leaves on several areas of your trees at least twice weekly. Ants tend aphids and collect their honeydew and large numbers of ants climbing up your tree trunk is an indicator that you may have aphids. Over watering and over fertilizing can increase aphid populations so only apply the minimum necessary for healthy plant growth.
One excellent way to reduce aphid populations is to knock them off with a strong spray of water.
Several natural predators feed on aphids including lady beetles, green lacewings, brown lacewings, syrphid flies, and soldier beetles. Predators can be released onto the trees but often appear naturally in significant numbers when there is a significant aphid population. Where aphid populations are localized on a few curled leaves or new shoots, consider pruning these areas out. Drop the infested plant parts in a bucket of soapy water. If insecticide sprays are needed, insecticidal soaps or horticultural oils are generally the best choice. Avoid using broad-spectrum insecticides which will kill natural predators and consequentially could increase your aphid population.
In our area, it can help to keep weeds under control near your trees.
With these tips, you can save your home orchard from an aphid invasion like the Men in Black saved earth from an alien invasion and go back to sleeping soundly throughout the night. Good luck!
Agriculture and Natural Resources, University of California (2019). Leaf Curl Plum Aphid. Retrieved from http://ipm.ucanr.edu/PMG/r606301811.html
Flint, Mary Louise (2018). Pests of the Garden and Small Farm: A Grower's Guide to Using Less Pesticide, Third Edition. Oakland, CA: The Regents of the University of California Agriculture and Natural Resources.
- Author: Dustin Blakey
I know you'll be glad to hear that there is a new garden pest in the Eastern Sierra. Well, it's native and so not technically new, but as far as I know, gardeners haven't had to deal with it in recent memory.
This insect is a stink bug with the gnarly name of Chlorochroa kanei. Don't try to say it quickly! As far as I know there is no common name for it. Characteristically it has a single dot on its back and a light border around its body. The color, at least this year, has been black, but dark green and brown variants are known to exist.
It normally feeds on the Great Basin plants in the desert, but this year it has shown up in gardens. We have seen it so far on English peas, artichokes and possibly potatoes. I tried to find a preferred host list for this pest and there wasn't really information. Other species of Chlorochroa do have preferred hosts figured out, but not this one.
If you encounter this pest, please let us know in the comments, and tell us which plants you found it on so we can better know what to look for.
Probably the best control in the garden will be to physically remove them and their eggs. UC IPM has some general information about stink bugs online here, but nothing on this particular pest. Information for those other species will apply here as well.
Chances are we may not see it again in the garden, but you never know!