Farmers going nutty about bats and birds
Results from the first year of a project on pests in macadamia orchards already provide clear evidence that crop damage increases when bats and birds are excluded from orchards.
WHITE RIVER – Scientists say that biological control using bats and birds, will reduce the need for macadamia farmers to spray their trees.
This will cut production costs and make a higher percentage of the crop processable.
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These are some of the findings of a collaborative research project between Green Farms Nut Company (GFNC), four of its suppliers, Samac and the University of Venda.
The project has been designed and is being managed by the university’s South African Research Chair’s Initiative chair on Biodiversity Value & Change under Prof Peter Taylor.
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The damage is caused by stinkbugs, moths and nut borers.
Graeme Whyte, GFNC development and client manager, said that farmers can improve profitability by as much as 10% by using biological pest control such as bats and birds.
Graeme Whyte
He explained that pest control via bats and birds is free.
“All you have to do is put up bat boxes in bat-friendly areas and grow indigenous bush next to your orchards. There is really is no downside to doing the environmentally responsible thing.”
Researchers Valerie Linden and Sina Weier have put up 48 cages around trees on six farms.
One set keeps birds and bats from feeding at all off the insects on and around the trees.
A second set enables both bats and birds to access the insects day and night.
The third set of cages is closed in the evenings, to exclude bats and nocturnal birds.
The fourth is closed during the day to exclude birds that are active in the day.
The nuts from the caged trees are sampled to establish the percentage of damage caused by insects under these controlled conditions.
“We’ve since established that certain species will also feed off the stinkbugs and that the bats will both catch the insects in the air and take them off the leaves of the trees. Various species of birds have the same habits,” said Linden.
She explained that based on this behaviour, the dietary analysis done on the bat and bird droppings, and the kernel damage patterns, it’s clear that the bats and birds make a definitive contribution to reducing crop damage.
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