This technical update by Soft Fruit Agronomist, Dr Neil Holmes, looks at how growers can unleash the power of Garlic as a natural deterrent
Trials in blueberry and tomato crops have shown a major reduction in the presence of pests when Gard S, a garlic extract available from OMEX has been applied either as a drench or through the fertigation system.
Applying a garlic extract at an early stage in the development of the pest population is essential to inhibit further colonisation of the crop and to successfully reduce pest pressure.
On average a 61% reduction in pest numbers has been observed in trials targeting Two-spotted spider mite and aphids. Application through the fertigation system saves time and labour, freeing-up spray operators to perform tasks elsewhere on the farm.
In tomatoes the Gard S application rate was the equivalent of 2.5L/ week applied at a dilution rate of 1%. In the blueberry trial Gard S was applied at an initial rate of 10L/ 1000L stock tank/ week and thereafter at 5L/1000L/stock tank/week and then applied at a 1% dilution to the crop during the pollination period to keep aphid numbers in check whilst also permitting bees to carry on pollinating the crop
Garlic is particularly rich in organosulphur compounds such as vinyl dithiins, diallyl disulphide, diallyl trisulphide and methylallyl trisulphide (Attia et al., 2012) which impacts upon the suitability of the crop as a host for pest populations. However, because these compounds can breakdown within 5-10 days of application, a weekly application is required to maintain the deterrence on pest populations. Prior research has also shown that there is a dose response effect, so too little applied each week, or too few applications does not have the desired effect.
For further information on Gard S and other products in the OMEX Horticultural range, please contact your local OMEX representative here.
Reference:
Attia. S., Grissa. K. L., Mailleux. A. C., Logany. G., Heuskin. S., Mayoufi. S. and Hance. T. Effective concentrations of garlic distillate (Allium sativum) for the control of Tetranychus urticae (Tetranychidae). J. Appl. Entomol. Vol. 136 (4) 302-312. 2012.