The 2020 onion season in the Western Bosveld region of Limpopo saw some exceptionally good results from STARKE AYRES onion varieties. Relatively few problems were experienced and those that were had no major effects.
Early season temperatures were high but not unusually so. The heavy, concentrated rainfall of previous seasons was less of a factor and early growth conditions were good. These favourable conditions led to good, even stands in most cases. The winter temperatures were lower and this caused slightly later maturities than expected. The cold winter was probably also responsible for the reduced incidence of serious thrips damage due to lower insect activity and longer life cycle periods. Almost no Iris Yellow Spot Virus infections were seen, also due to reduced activity of the thrips vector. Leaf diseases were generally well controlled and most crops reached falling stage with a healthy leaf canopy still intact. The extra cover allowed for better curing of bulbs and overall quality was high.
As in most years, the quality of results improved as sowing dates moved from early February through into mid-March. The first sowings of any year are the most likely to be subject to harsh conditions, with high temperatures, humidity and heavy rain showers all contributing to seedling mortality. Diseases such as damping off are also most serious at this time of year. Rapid development of weeds has to be controlled by herbicides and this can also affect early development. Later plantings experience milder conditions and populations of these are usually closer to target.
The varieties STAR 5516 and CRISTALINA have been used with great success in the area and again delivered fine crops. These two varieties are used for the first main season sowings due to hardiness of seedlings. SOBERANA is a great favourite for sowing in the later slots. It is very resistant to bolting and this is an important attribute as the later the sowing date is, the greater the danger of bolting.
Red onions are still a relatively minor component of the onions produced in the Bosveld but are nonetheless important. The varieties MATA HARI and RASTA have been dependable performers and were so again this year. Both are quite significantly slower to mature than the yellow varieties and should be planted in such a way that irrigation can continue after yellow varieties have fallen. The red varieties should be sown earlier rather than later due to the longer growing period.
Although the present varieties have done well, the search for improvement never stops. Many thanks are due to all the growers who assisted with the trial programme this season. Without this work, new varieties will never see the light of day.