With a host of issues, including drought and an unexpected disease outbreak in many orchards, the industry’s leadership says each region has had to deal with unique, and, at times, devastating challenges.
South African Macadamias (SAMAC) CEO Lizel Pretorius said a revised crop forecast was carried out in March.
“The figures had dropped to 62 000 tons and now after the second quarterly crop forecast it is at 49 503 tons nut-in-shell (NIS measured at 1.5% kernel moisture content). This is about 16% lower than the 59 050 tons harvested in 2019,” she said.
It was difficult to pinpoint which of the growing regions was hardest hit, with Limpopo province still in the grips of a crippling drought and further climate change impacts playing out on the KwaZulu-Natal North Coast.
“All in all, there has been a host of issues in all provinces, including Mpumalanga, ” she said.
With investigations under way to establish the reasons for the harvest reduction, Pretorius said many orchards had reached maturity and the rejuvenation of the trees was necessary to increase their production.
“Older and denser orchards have many disadvantages if they are not properly pruned. They are susceptible to an increased pest and disease load, as the production front gradually moves upwards and therefore out of reach of sprayers. The trees start to compete and increase their foliar growth rather than reproducing, and the inside and bottom of some of these mature trees dies off, meaning a drop in their yield.”
Old orchards that have passed their optimal production have resulted in lower crop yields this season.
Heat and drought
Although the recorded rainfall this past season was considered average, it is now presumed the effects of the 2016/2018 drought are still lingering.
Pretorius said underground water had yet to replenish fully to levels measured prior to 2016, at the onset of the drought.
“Adding to this, many production regions recorded high temperatures during flowering. This may have affected more sensitive flowers, leading to abortion in heat-stressed trees.”
Group Agricultural Technical Manager at Green Farms Nut Company Barry Christie said unpredictable weather conditions had played havoc with the crop, resulting in many farmers reporting reductions of between 20% and 50% as a result. The Beaumont variety was especially hard hit, he said.
“Excessive heat in October, just after fruit set, resulted in a big nut drop. We also saw extreme variations in minimum and maximum temperatures, leading to thicker shells and smaller nuts. A one-millimetre difference in shell thickness makes a massive difference to crackouts,” Christie said.
Further, a novel fungus made an unwelcome appearance during the harvest season, which, he said, was presumably brought on by the variations in temperature.
“We started noticing farmers were bringing in nuts with a kind of fungus on them that made the shells darker than usual. Some looked fine initially, but then within a day or two they started to darken. The fungus penetrates the shell, affecting the quality of the nuts.
“We suspect the fungus has something to do with the farms’ drying bin set-ups. Drying the nuts is a very technical process and knowing when to switch the fans on and off can be tricky if there are no built-in sensors to control the fans and heat. Because of the big variations in temperature, I suspect with the cooler evening temperatures there was more condensation at night, and if the fans were switched on too late, this could have brought on the fungus,” Christie said.
With the country now in the grips of a colder winter than usual, the Lowveld region has reported frost on lower lying orchards, damaging a large number of the trees.
He said smaller trees, especially in the Barberton district Mpumalanga, were particularly affected.
“I have never seen frost damage on such a scale as this. It could push production back in the future because those trees have lost growth.”
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