Pesticidewise: spraying pesticides upwards using a knapsack sprayer

Pesticidewise: spraying pesticides upwards using a knapsack sprayer


This video will show you how to spray
pesticide upward but using water to practice with. You will need your pesticide label; your knapsack sprayer; clean water and personal protective equipment (PPE) as
directed by your pesticide label. From the pesticide label you also know:
the amount of pesticide to be applied; the water volume rate to use and the type of nozzle advised. You will have used some of this information to find out the size of nozzle you need and so will now also know: your row or swath width, or the with the canopy that you will be
spraying; your comfortable sparying speed; your nozzle flow rate and the knapsack
sprayer pressure or pumping rate. In this demonstration the label advises us to use 75 ml of contact insecticide in 400 L of water to the hectare of treated area or 400 ml for every 10 square meters of treated area, to control whitefly in tomatoes. The label advises the use of a hollow cone nozzle to spray fine drops. We have calculated that the nozzle size we need has a flow rate of 0.6 L/minute (or 10 ml/second). The swath width produced by the nozzle is 0.5 meters and the knapsack sprayer will be pressurized to 1.6 bar The foliage of this section of the tomato row is 10 m long and 1 meter wide which is a total of 10 square meters. To apply 400 ml to this area, we have calculated that the operator will need to spray for 40 seconds and so should spray each side of the row for 20 seconds each. When practicing spraying only use clean water and wear your PPE so that you get used to wearing it and can adjust it so that you are comfortable. Some pesticide labels will permit the use of long sleeved shirt and trousers as dedicated PPE. A better option is to wear a coverall. This knapsack has already been cleaned, checked and calibrated. If you are not familiar with how to do this, please have a look at our separate videos. The operator will be spraying upward and
laterally with the nozzle 50 cm from the foliage. It is really important that you wear the
correct PPE when spraying upwards. This is because in order to spray the tops of taller trees, you will need to angle the
spray projection steeply upwards. Whilst some spray will be projected
safely upwards for up to a meter, some drops will fall back down. Wear a coverall with a hood and make sure that the hood is pulled up and over the head. The sleeves of your gloves should be on the outside of your coverall sleeves or you could use tape to close the gap between sleeve and glove. When practicing to spray upward and latterly with water, start at the top of the foliage and move the nozzle down… then move the nozzle across half a meter and spray up… then move the nozzle across half a meter and spray down. For higher foliage you may need to fix
an extension to your lance. Extensions enable the nozzle to be
positioned closer to the spray targets in the highest points of the canopy. Keep the nozzle about 50
cm away from the outer leaves of the canopy to achieve the full width
of the swath – in this case half a meter. The intensity have small fine size drops generated by hollow cone nozzles and the angles of their projection ensure that the leaves at the front of the canopy and the concealed leaves within are all sprayed. Monitor you spraying pressure and keep you spraying speed constant. Constantly check that your nozzle is producing the right spray pattern and drop size. Be careful not to spray the ground nor to spray over the top of the row as
this will waste your pesticide and be a risk to the environment or
anyone near you. Where you are spraying crops in a row like
these, spray first one side pf the crop in a row and then go
to the other side of the row and continue spraying. Check that every leaf is sprayed and has a cover of drops. Check that spray is reaching all the leaves within the canopy; those that are lower down as well as those at the top; and those on the outer side as well as those within. If some of the leaves have received too much pesticide like this one where the drops have
accumulated and dripped off onto the ground then the nozzle was being moved too slowly. Practice again until you have the best deposits on the leaves. This contact acting insecticide needs to
be sprayed using smaller drops to produce an almost complete cover of drops over every leaf. All contact pesticides will only control the pest where the sprayed drop has made direct contact with the pest so check that every leaf and stem has a
cover of drops over the entire target surface. When air is coming out of the nozzle and the spray liquid is all used, place a stick at this point to mark where spraying must restart with the next load. Leave a small un-sprayed area which is to be sprayed later with the water used to clean the inside
of the sprayer. © 2015, Syngenta. All rights reserved.

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