There are grasshoppers in the fields of the area. The grasshoppers are doing damage to the crops in the area. It is time to get out and check to see if there are problems in your fields.
The first step in dealing with grasshoppers is to find them. The grasshoppers are usually concentrated around the edge of the fields. This year is very different. We are seeing grasshoppers scattered throughout the fields. This means that the whole field will need to be checked to ensure that problem areas do not appear later in the season.
When looking for grasshoppers, the best way to check is to do it while you are walking. If you are taking steps that are about a meter long, count what jumps up in front of you. This number will give you a count that represents the number of grasshoppers per square meter. This number what the research for economic threshold levels are based on. Numbers of between 6 and 12 will usually justify spraying in any crop.
When grasshoppers are little, it is difficult to check their numbers because they are too small to see. They are also not doing a lot of damage to the crop at this growth stage because small grasshoppers do not eat a lot. Grasshoppers that reach over a half inch in size indicate that the population of grasshoppers is nearing the end of its hatch. Also, this is when a grasshopper population starts to eat significantly more. This is the time when spraying should be considered if the damage is becoming evident.
With grasshoppers, there are times when the economic threshold for controlling the insects should be ignored. If the crop is growing well and the damage is minimal, it might be best to leave the grasshoppers alone. When critical levels of grasshoppers show up in a field, the crop looks like it is standing still.
When the grasshopper numbers are low, but plants are being chewed off before they can establish, spraying may be required below the economic threshold. Knowing the numbers of plants that are essential for good yields will help determine if the grasshoppers should be controlled. Having a poor plant stand means that a producer will likely see more benefit from controlling grasshoppers earlier at lower population levels.
The most common fields that we are seeing grasshoppers in are fields that were in grass and taken out of hay production in the last couple of years. These fields seem to be the most common sites for finding higher populations of the insect.
Check your fields. If you see grasshoppers and you are not sure if you have a problem, give your local agronomist a call. Using insecticides in the proper fashion is important to all of use. Spraying this insect when appropriate will help a producer grow more bushels.
By Dave Cubbon, P Ag