Spiders are often feared by the general public. But they do a lot of good in the orchards. Recent work done with our project has shown that spiders are voracious eaters of many pests including moth larvae such as codling moth. (See "Codling Moth: its what's for dinner") The 50 or more spider species that might be present in a moderately sized organic orchard can be divided into two large groups: web-makers (about 55%) and hunting spiders (about 45%). Web-makers construct large silken webs (the design is often characteristic of that species). Their prey fly or fall into the webs and are stuck until eaten. Although hunting spiders also produce silk, they don't build webs to catch their prey. Instead they use their legs and mouthparts to capture prey.  Some hunting spiders actively pursue their prey, while others use a sit-and-wait prey capture strategy allowing the prey to come to them.

Orchard workers often wonder were the spiders suddenly come from later in the season after not seeing them earlier. This is because Spring hatching spiders develop slowly and only become more noticeable after they have grown larger and started building bigger webs. This also gives the mis-perception that they only have web building spiders present, when in fact the hunters are all over the trees and orchard floor. Unlike the orchard insects, spiders only have a single generation per year. They overwinter as adults. Egg sacs may be laid either in the fall or in the spring. This is important to know from a management standpoint because harsh sprays early in the season may kill off the spider populations. Re-establishment of spiders would be a slow process. As part of our project, we included two spider species (Misumenops lepidus and Pelegrina aeneola) in our pesticide effects study. Knowing the impacts on spiders would give managers the ability to choose a pesticide  less harmful to the spider populations.

The gallery below is made up of images showing examples of the species most likely found in western orchards. We've tried to use our own images, but have included many taken from
Bugwood.org and Bugguide.net under the common use copyright agreement. Please refer to the applicable website for reuse of any of their images. If you would like to use our images, please check with us first.

Scroll through images using the arrows or click on thumbnails.

Permission Required to Reuse Images

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