South Africa is the world’s third largest producer of
macadamia, Macadamia integrifolia (Maiden & Betcke) nuts. Like
most commercial crops, macadamia is subject to infestation by pests. About 60
insect and two mite species are known to attack macadamia trees and their
fruit.. In South Africa, pentatomid and coreid stinkbugs are the most important
pests in macadamia orchards. Infestation results in young nuts dropping and
older nuts developing lesions. Orchards are populated by numerous spider species. Reviews on
the role of spiders in agroecosystems indicate an increasing interest in, and
recognition of, spiders as natural control agents of insects and mites in such
systems. In South Africa, spiders occur in abundance on commercial crops,
including tree crops such macadamia. However, little information is available
on spider assemblages in macadamia orchards, both locally and elsewhere.
Considering the vast number of insect species that attack macadamia in South
Africa, it seemed the ideal crop for investigating the implementation of natural
control with spiders. The important first step in such an endeavour is to
determine spider species diversity and abundance. Spiders we collected over a 12-month period (1997-1998) from
three macadamia orchards in the Mpumalanga Lowveld in South Africa using
dichlorvos as a knock-down spray. Of the 2778 spiders collected, 2020 belonged
to the Salticidae, representing 73% of all spiders collected. The salticids were
the richest in species with 17 species, of which four species represented more
than 61% of all spiders collected. Thyene coccineovittata Peckham &
Peckham was the most abundant species and represented 30% of all the spiders
collected followed by T. natali Peckham & Peckham with 14%, Viciria
alba Peckham & Peckham with 9% and Tusitala guineensis Berland
& Millot with 8%. These four species were present throughout the year in all
three the orchards. Spiders form part of the natural enemy complex in macadamia
orchards in South Africa. Studies worldwide indicate that spiders play a role in
the suppression of insect pests and that generalist predators such as spiders
can limit exponential increases in pest populations and need to form a part of
integrated pest management strategies in agro-ecosystems. Read more:
Dippenaar-Schoeman A S, Van den Berg M A,
Van den Berg A M & Van den Berg A. 2001 Spiders in macadamia
orchards in the Mpumalanga Lowveld of South Africa: species diversity and
abundance (Arachnida: Araneae). African Plant Protection 7(1):
39-46. [ 1Spiders in macadamia orchards.pdf] Dippenaar-Schoeman A S, Van den Berg M A & Van den
Berg A M 2001. Salticid spiders in macadamia orchards in the Mpumalanga
Lowveld of South Africa (Arachnida: Araneae). African Plant Protection
7(1): 47-5. [2Spiders in macadamia orchards.pdf] | 
