Spiders are found in and around grape vineyards. They prey on
insect pests that are found associated with grapes. However there is an
increased frequency of finding spiders in containers of exported table grapes.
When the grapes are harvested some spiders are able to escape detection during
the packing process. The spiders hide in silk retreats made in the stems of the
grapes. The grapes are chilled prior to transporting causing the spiders to
become dormant and immobile. However, spiders are able to lower their metabolism
enabling them to survive long periods of low temperatures. When the exported
containers are opened at the retailers or consumers the spiders become active
after this period of inactivity. They are then observe seen when they try to
escape. The first author receives annually several queries from grape exporters
regarding spiders exported on grapes.
Spiders are common predators find in agro-ecosystems worldwide
and they are known to play an important role in controlling pest species . They
are present in high number in most crop systems as also found in Southern
Africa. Nothing is known from vineyards in Africa and our present knowledge is
from research undertaken in southern Germany and central California.
During a recent survey undertaken on the border of Namibia and
South Africa a total of 106 spiders represented by eight species from six
families were collected from grapes. Two species Cheiracanthium
furculatum (Miturgidae) and a unidentified Theridion sp.
(Theridiidae) constituted 86% of all the spiders collected. Two of the species
collected C. furculatum (sac spider) and Latrodectus
geometricus (brown button spider) are listed as of medically importance in
Dippenaar-Schoeman, A.S. & Mansell, M. (in
preparation).First records on spiders from grapes in Southern Africa
Miturgidae: Cheiracanthium sp.
Spiders in Agro-Ecosystems
Spiders in cotton orchards
Spiders in avocado orchards
Spiders in macadamia orchards
Spiders in pistachio orchards
Spiders in strawberry fields
Spiders on citrus orchards
Spiders as predators of termites
Spiders as predators of mites