Water quality of spray solution is very important factor for the effective performance of the insecticides used to manage insect pests. Especially the pH of the water solution used for spray mix, particularly with insect control is very important factor.
Many pesticides available in the market are in concentrated form and required to be dissolved or added in water at recommended rates and then used on crops. The water which is used as spray mix may be from different sources like bore well, rivers, tanks, rain water, pond water …etc.
The water have some important parameters like dissolved minerals, Organic matter and pH to be considered for the usage. These parameters will be in different quantities and values based on the source of the water. pH of the water to be used for spray mix is more critical factor for effective performance of the pesticides which will be used on plants.
What is pH?
pH of water may be defined as the measure of acidity and alkalinity of that particular water determined by the presence of hydrogen [H+] ions and hydroxyl [OH-] ions in the solution. The measurement of pH is counted from 0[Zero] to 14 [Fourteen]. Solution with pH measured at 7 is referred as neutral, lesser than 7 is acidic and more than 7 is alkaline.
Why pH is important for pest control?
pH of the water which has to be used as spray mix solution, sometimes affect the stability of some pesticides. Pesticides which fall under the groups of organophosphates, pyrethroids, carbamates, and some of the growth regulators have shown poor performance at alkaline pH of the spray mix water. These pesticides’ molecules are said to undergo hydrolysis, getting broke down to inactive forms in pH more than 7. The inactive forms of gthe pesticides won’t perform the work they are are supposed to do.
Reports say pesticides breakdown more rapid at pH more than 7. The breakdown of the pesticides may be faster and faster as the pH value go more and more higher than 7. The rate of hydrolysis is increased more than time for increase in one unit. Many pesticides starts to breakdown by starting of mix in water.
How pH can be estimated?
Easiest method and fast method of estimating the pH of the spray mix is with pH test paper or pH meter. Once the pH is estimated, then it can be adjusted with acidifying or buffering agent. Then the pesticides can be mixed in to the solution.
What is the optimum pH for spray mix for effective pest management?
A safe pH for a spray mix solution is 4.5 - 7.0, with the best pH reading in the 5.0 - 6.0 range. Majority of the pesticides perform best at this range.
How pH can be regulated in spray mix solution?
Buffering agents, Multiplex equvinox, is the pH neutralizing agent which may stabilize or regulate the spray solution at a predetermined pH and keep it at that level.
- Follow the using directions provided in the label of the product.
- Stir the spray mix during adding the pH regulating agent and record the pH.
- Generally have the check of pH of the water which will be used as spray mix.
K SANJEEVA REDDY,
Senior Agronomist, BigHaat.
Disclaimer: The performance of the product (s) is subject to usage as per manufacturer guidelines. Read enclosed leaflet of the product(s) carefully before use. The use of this product(s)/ information is at the discretion of user.
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