By Jasper Raats
After the generous rainfall over the past week across Limpopo and Mpumalanga’s Lowveld and parts of KwaZulu-Natal, farmers must adjust their orchard management and spraying programmes to control water-related diseases and insect pests, says Dr Elsje Joubert from the Levubu Centre for Excellence.
She warns that she and her team have noticed many new egg clusters, especially from stink bugs, in macadamia orchards in the Lowveld over the past week. “Sticking to a prior fixed spraying programme could lead to major insect damage,” she warns.
“There were relatively few insects in the orchards before the first proper rain in December, but it’s as if the moths and stink bugs were waiting for the rain.”
Macadamia growers must be ready to target pests like the two-spotted stink bug in their nymph stage, and the timing must be optimal for this. Scouting to determine how many eggs have been laid and when they’ll hatch is essential for quick and effective response, she says. Joubert. The same applies to nut borers. “One only needs to look at how many moths of all kinds are now around the lights at farmhouses in the Lowveld at night to realise that the pupae were lying dormant in the ground waiting for rain.”
Joubert says the advantage macadamia growers have this year is that the nuts are bigger than usual for the season. Trees are also no longer aborting nuts as they set slightly earlier than usual. Therefore, she expects good kernel yields if farmers intensify their scouting and treat what they see in the orchards rather than sticking to pre-planned spraying programmes.
Avocados
Joubert says that avos are also a bit earlier than usual in most areas this year, which could lead to larger fruit with a better pack-out percentage.
She warns, however, that Phytophthora is a significant risk for avocados in the current wet conditions. If orchards don’t have good drainage, producers could suffer damage. She advises farmers, especially in KwaZulu-Natal, to dig drainage ditches in their orchards to drain standing water.
“Farmers must also establish a good mulch layer in their orchards by spreading as much compost and plant material as possible under the trees. As you can’t get into the orchards with equipment now, it will have to be done by hand, but it will help a lot when the trees push out new roots in February.”
