This Ds-mix, made of Ds-Lime, Cuprum and ManZincum, has been especially developed to increase the plant’s natural defence to spotted-wing drosophila.
The pH level is increased due to the lime (97% Ca(OH)2). Application of
150 grams of Ds-Lime in 100 litres of water achieves a pH of about 12 on the leaf. This has no adverse effects on the leaf and the fruit but results in asphyxiation of the SWD eggs and larvae.
The elevated pH is also detrimental to fungi such as powdery mildew (which cannot survive at a pH of 12) and botrytis (which survives less well at a pH of 12).
Cuprum and ManZincum
Add 250 ml Cuprum/ha + 750 ml ManZincum/ha. The particles in the micro copper (Cuprum), micro manganese and micro zinc (ManZincum) stick to the leaves like small magnets.
This results in the following effects:
- The lime stays on the leaf for much longer – not for two days as when only lime is used but for six to seven days. Due to the Cuprum, the product also spreads more easily over the leaf and adheres better to the leaf surface.
- Research seems to indicate that the elevated pH cauterises the respiratory tubes of the drosophila larvae and the eggs, resulting in asphyxiation.
- Because the incidence of botrytis (see ‘Ds-Lime’, above) is also reduced, fewer fruit volatiles are released that attract the drosophila to the plant, making the traps more attractive.
- Mn and Zn have a repellent effect on insects in general, therefore not only on drosophila, but also on red spider mite, gall mite and wasps. Wasps in particular damage healthy fruit, which releases extra scent signals that then attract more SWD. Fewer wasps therefore means fewer scent signals and fewer drosophila.
||150 g/100 litres water
||250 ml/ha (>750 litres water: 350 ml Cuprum/ha)
||750 ml/ha (>750 litres water: 1 litre ManZincum/ha)
Ds-mix spraying schedule
Ds-Lime, Cuprum en ManZincum, combined with traps
|Period of application:
||from first fruit/capture of first SWD to end of harvest
||every 7 days
||150 g/100 litres water
||< 750 litres water/ha: 250 ml Cuprum/ha
> 750 litres water/ha: 350 ml Cuprum/ha
||< 750 litres water/ha: 750 ml ManZincum/ha
> 750 litres water/ha: 1 litre ManZincum/ha
| Amount of water/ha
||Depending on production and spraying method:
350–1,000 litres water/ha
Advantages and tips
Comprehensive approach using Ds-mix:
- Use traps
- Hygiene measures: remove overripe fruit
- Apply Ds-Lime – leaf fertilizer with repellent effect on SWD
- Apply Cuprum – leaf fertilizer that increases plant’s resistance to bacteria and fungi
- Apply ManZincum – leaf fertilizer with repellent effect on SWD, red spider mite and wasps
- Spray on dry crop (no dew) and during not too hot and sunny weather to prevent lime deposits on cherries, blackberries and redcurrants, which are more susceptible to this than strawberries, raspberries and blueberries. The instructions can therefore be followed less strictly for these crops.
- This dosage of Ds-Lime (150 grams) in 100 litres of water leaves no residue.
- There is no safety term before harvest.
- The trial site strawberries were presented to a taste panel:
- no member of the taste panel did not like the strawberries (i.e. they all liked them)
- 90% of the tasters could not taste any difference between the treated and untreated fruit, and
- 10% noticed a slight difference but could not identify anything specific
- Ds-Lime has no impact on natural predators.
- Due to the positive charge, the particles remain active on the leaf for much longer.
- Low price per ha: ca. € 60,-/ha.