United Kingdom
April 30, 2020
Drought stressed onions are particularly susceptible to thrip infestation and larvae damage
A new label approval for the innovative Syngenta insecticide, Minecto One, now gives allium growers of bulb and salad onions, garlic and shallots an important option for effective thrip control.
Minecto One has proven extremely valuable in recent seasons, for control of chewing pests in brassicas, including caterpillars and cabbage root fly, along with carrot fly in specified root crops and pea moth in vining and podded peas. Well timed applications have also shown useful incidental control of a range of aphid species in approved crops.
The new approval in alliums enables one application of up to 310 g/ha, timed at the first sign of attack, from the second true leaf growth stage, up to full leaf senescence. There is a 14 day pre-harvest interval.
Syngenta Technical Manager, Dr Max Newbert, highlighted thrips (Thrips tabaci) have become an increasing issue for onion growers over recent seasons, during prolonged dry periods causing stressed susceptible crops. From May the pests can invade crops and go through several generations over the summer in conducive conditions; egg to adult can take as little as 15 days.
“An effective early start to the thrip control programme can help to minimise risks for the season,” he advised.
“But growers’ options have been limited in recent years. Minecto One will prove an extremely welcome option to quickly target large populations of thrips migrating into the crop.”
Importantly, Minecto One controls both the adult thrips directly feeding on the treated crop, as well as any hatched larvae feeding in the leaf. It will be especially useful where efficacy of other knock-down insecticides has been seen to be reduced in previous seasons.
For highest levels of efficacy in allium crops, Dr Newbert advocates application with sufficient water volume to achieve good coverage of the leaf area, but avoiding excess run off on waxy surfaces. Minecto One’s xylem systemicity will help to target thrip sucking pests, as well as achieving better spreading and penetration into crops.
Syngenta application trials have assesed effects of water volume + speed and nozzle choice on spray deposition at different target zones in the onion crop canopy
Dr Newbert reported Syngenta application trials in alliums have shown water volume, using a coarse nozzle and forward speeds of around 10 km/hr are most effective to target pests in the crop crown. Adjuvants, such as a high % methylated rapeseed oil, have been shown to help spreading and penetration into the crown.
The maximum total dose for Minecto One for alliums is specified as 310 grammes of product per hectare per year. As an anti-resistance measure, the label states any land treated with Minecto One at the maximum total dose must not be treated with any other cyantraniliprole containing products in the same calendar year, he pointed out.
“Having created a new mode of action for this crop and pest, it’s essential to protect the ai, especially with resistance to spinosad and pyrethroid insecticides already having been observed in thrip populations,” Dr Newbert advised.
Utilising good irrigation scheduling to avoid crop moisture stress and alternating treatment modes of action using available products, he believes effective thrip control can still be achieved.
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