Knapsack spraying tomatoes

The pattern and density of planting tomatoes as well as the cultural methods used are all going to influence how you select, adjust and use your sprayer.

Leaf canopies of tomatoes develop very quickly. In a few days, the leaf canopy can become so dense that it forms a barrier which prevents spray drops penetrating into the centre.

This makes it very difficult to control any pests and diseases at the centre of the crop as here. If unchecked, this reservoir of pests will cause a rapid re-infection of the whole plant despite a good cover of spray drops on all the outer leaves.

Higher water volumes are essential for dense leaf canopies like these.

A lot of the spray is caught by the outer leaves, less spray, but still an adequate quantity, is caught by the leaves half way to the centre. But, to get drops here into the very centre of the plant and on the underside of leaves, the drops need to be smaller, lighter and more buoyant; these drops have a greater ‘wrap around’ effect enabling them to reach the hidden target surfaces. This is why, as the crop develops, you are likely to need to increase water volume. To produce these smaller drops, you need to use the right nozzle with higher water volumes and higher pressures as directed by your pesticide label.

The problem with smaller drops however, is that they are more likely to drift in wind or evaporate in high temperatures and so you must pay particular attention to the weather conditions at the time of spraying. Have a look at our 5 day weather and spray conditions forecast for more information. For more information about using pesticides and which PPE to use, visit our website: www.pesticidewise.com