Comb-footed spiders
Systematic position. The family Theridiidae, commonly known as comb-footed spiders, belongs to the order Araneae. While these spiders are primarily insectivorous and often serve as natural predators, in high-density agricultural environments or greenhouses, they can become a management concern due to their extensive web-building activities which interfere with crop maintenance.
What the section contains
Black widow spider
Latrodectus mactans
Black widow spider
Latrodectus
Brown widow
Latrodectus geometricus
Cobweb spider
Achaearanea
Common house spider
Parasteatoda tepidariorum
European black widow
Latrodectus tredecimguttatus
Parasteatoda
Parasteatoda
Redback spider
Latrodectus hasselti
Steatoda
Steatoda
Steatoda paykulliana
Steatoda paykulliana
Tropical black widow
Latrodectus curacaviensis
Western black widow
Latrodectus hesperus
Comb-footed spiders
Crops and damage profile. These spiders are frequently found in greenhouses, vineyards, and ornamental plant nurseries. The primary damage is not feeding on plant tissue, but rather the construction of dense, tangled webs that wrap around leaves and stems. This physical barrier blocks sunlight, restricts air circulation, and traps moisture, which can lead to localized fungal growth and necrotic spots on foliage.
Biology and lifecycle. The lifecycle consists of egg, nymph, and adult stages. Theridiids are known for their intricate, three-dimensional webs. They thrive in protected, humid microclimates within plant canopies or structural gaps in greenhouses. Their reproduction is highly successful in stable environments where they can hide their egg sacs securely within plant folds or structural crevices.
Economic importance. In commercial horticulture, the aesthetic and physical impact of webbing is significant. Ornamentals covered in webbing lose their market value immediately. Furthermore, the persistent presence of spider webs can serve as a refuge for secondary pests like aphids or whiteflies, protecting them from predatory insects and reducing the efficacy of biological control agents.
Protection measures. Management strategies should focus on habitat disruption and environmental control to discourage colonization. Effective methods include:
- Regular mechanical cleaning of greenhouse structures to remove webs and egg sacs.
- Improving air circulation and regulating humidity levels to make environments less suitable for spiders.
- Sanitation protocols that include removing weeds and debris from the greenhouse perimeter.
- Strategic pruning of infested plant parts to reduce the available surface area for web construction.