How to spray chemicals effectively

but very little on the lower leaf surface where pests such as spider mites, aphids and whitefly spend most of their time, and where many diseases occur.
If instead, the nozzle is held near the base of the plant being sprayed and pointed upwards, some of the spray will land on the lower surface of the leaves.
The spray that misses the leaves on the way up will land on the upper surface of the leaves as it falls back down.
The V lance is a simple adaptation, which allows the spray to be directed upwards.
It consists of a swivel joint and a thread adapter, which are fitted between the lance and the nozzle.
When joined into the V position, it is easy to spray upward into crops such as kale and tomatoes, and also into other crops such as egg plant and beans.
Studies have shown that both spray distribution and pest control are improved compared to plants sprayed with a conventional lance.
Such improvements in effectiveness open up the possibility of using lower doses of pesticide or fewer sprays.
This in turn helps to reduce pest management costs, human and environmental safety risks and helps the spraying to be selective and effective in controlling pests and diseases, but with minimum damage to natural enemies or other beneficial organisms.
Experts say that it may not be necessary to get spray onto all parts of the plant.
If enough is known about the pest or disease, spray can be directed only on the affected parts of the crop, the chances of natural enemies surviving will be improved.
When a particular layer of the crop is treated, this is known as spray stratification.
If spray is only applied to areas of the crop where the pest or disease can be seen, this is called spot spraying.
These partial cover sprays can also help the spraying to be more selective.