We chose 4 most typical trees which didn’t differ from each other. All of this 4 trees were marked with 6 spots for sampling. Spot 1 was on the outer side of the crown on the bottom, spot 2 was inside the crown, spot 3 was on outer part of the crown in the middle, spot 4 was in the middle of the crown, spot 5 was on the top of the crown and last 6th spot was inside the crown on the top.

Each of this spots had clipped 4 clippers. One of them held 2 water sensitive papers, which were positioned to one another. Other 3 clippers held each 3 apple tree leaves, which were torn away in the same cultivation, far from the spot where we carried out the test.

Deposit of spraying agent Quality Analysis with coloured tracker.

In the picture you can see 3 clippers, each with 3 apple leaves.

Three leaves were clipped in each of the clippers. The clippers were clipped in six points in the crown of the tree. The leaves were clipped on the peduncle. When test spraying was finished we removed the leaves and put them in PVC bag and store them in a cooling bag, so that no light could access them. Laboratory analysis followed 20-26 hours after the bags were stored. We exchanged the leaves for every version of spraying test with new ones, so that we had 9 clean leaves, which were taken from the same tree type in orchard.

We got analytic solution of tartrazine which was washed from the leaves by pouring the PVC bag with 9 leaves with 100 ml of distilled water and with shaking of the bag for 30 seconds. We achieved effective dissolution of tartrazine deposit. After this we vacuumed 20 ml of liquid with help of a modified filter. We injected this solution into cuvette for readout in photo spectrum Varian Carry 50 (Varian Inc., USA). The Tartrazine dye readout was carried out at wave length absorbance 430 nm.  Because of the fact that the PVC bags were poured with 100 ml of water, we could calculate how much of tartrazine was in each PVC bag (micro grams). When we divided the total quantity of tartrazine with the surface of all 9 leaves we got the information about micro grams of tartrazine on cm2 (leaves surface).

The method for determining the quality of deposit using water-sensitive papers (WSP)

This method is more known to You

After the end of each test we took water sensitive papers from the tree. We stored them in envelopes in dry place and analysed them with help of Image analyser device. This was carried out in IHSP Žalec. The device analysed three spots of 1cm2 on each of the leaves in order to determinate the density of drop hits (n/cm2) and cover rate (%) and calculated statistical average value of the two studied parameters mentioned above.

Both methods complement each other. Analysis of quality of the spray mixture deposit, gives us information in which spots the deposit is OK, the method for determining of the quality of deposit with WSP tells us whether the deposit is better on upper or lower side of the leaves.

Are You eager to learn, which spraying speed is optimal so that the deposit on the plants is the most effective? Yu can find out this in next issue – issue nr. 4.

Zupan Sprayers wish You a nice and successful weekend.