Articles
SOME PROBLEMS IN THE PRODUCTION OF TEMPERATE FRUIT IN THE HIGHLANDS OF ZIMBABWE
Total sales for 1981/82 were 6 500 tonnes, comprising apple, peach and nectarine, plum, pear and apricot – in order of decreasing volume.
Almost all was consumed locally.
Major production constraints are discussed.
Climatic factors include inadequate winter chilling, counteracted with only moderate success by the application of DNOC/oil and other chemicals by most farmers.
Significant rainfall occurs from October to April only, with considerable local and seasonal variation, necessitating supplementary irrigation and/or mulching.
Hailstorms are commonest in early summer, causing appreciable losses.
Fruit cracking, especially on apricots and some apple and plum cultivars, can be severe; it is usually attributed to soil and atmospheric moisture fluctuations.
Most cosmopolitan pests are readily controlled with standard remedies, but fruit piercing moths of several genera, root knot nematodes (on peach) and mole rats (Dryptomys hottentotus) pose serious problems, while red spider mites are increasing in importance.
Among diseases, Armillariella root rot, apple powdery mildew, apple scab, Alternaria spot and Botryosphaeria dieback of apple, and various bacterial infections of stone fruits are the most difficult to control.
Weeds such as Cyperus spp., Pennisetum clandestinum and Cynodon dactylon are proving difficult and expensive to control by either chemical or mechanical means.
The range of scion and rootstock material now available in Zimbabwe is extensive, comprising cultivars from the Old and New Worlds plus a few local selections.
The main constraint to the introduction of much-needed new cultivars for evaluation in a range of localities – particularly for the export market – is the risk of bringing in hitherto unrecorded pathogens (especially viruses and mycoplasmas) which existing quarantine and ancillary phytosanitary facilities are inadequate to detect.