Garden Spiders

• The spiders most frequently found in garden environments belong to the argiope group of spiders. Gardens provide species like Argiope aurantia, the black and yellow garden spider or Argiope trifasciata, the banded garden spider, both their preferred habitats and their most common food sources such as aphids, flies, grasshoppers and bees. Female argiopes can often be observed in its orb-shaped web, but since they prefer not to be seen by humans, argiopes may need to be identified only by its egg sacs.
  
  

Egg Sacks

• The yellow and black garden spider's egg sacks are up to an inch long, sometimes containing over 1,000 eggs. Sacs stay intact until young spiders emerge in the spring. A single argiope produces 1 to 3 egg sacs per mating season. If you find an argiope egg sac in your garden, it will most likely be suspended in the argiope's web near the female argiope rest area. If you notice the egg sac after the spiderlings have emerged, they will resemble adults in color.
  
  

Argiopes in the Garden

• Argiopes are considered especially beneficial because they feed on insects that often damage plants, such as aphids. Since argiopes will almost never bite humans and since their bite is harmless, leaving your argiope population intact offers a risk-free and environmentally friendly means of pest control in your garden.
  
  

Other Considerations

• Argiopes are so common in garden ecosystems that they are colloquially called garden spiders; of course, there are other species that could potentially be responsible for the egg sacs that you observe in your garden. The black widow, for example, leaves egg sacs in their outdoor breeding sites. If you wish to err on the side of caution by removing any egg sacs you find in your garden, vacuum them up and discard the vacuum bag immediately.