Clemson University researchers are looking at the efficacy of injecting insecticides under a pumpkin crop in irrigation water.
Admire is one of several insecticides currently on the market that are in the same neonicotonoid family. Like many insecticides, neonicotinoids have shown a tendency to develop resistance problems when used too frequently. Smith stresses that a number of neonicotinoid insecticides can be used instead of Admire, but these materials should not be used in conjunction with it.
The injection rate of Admire is based on the number of linear (row) feet per acre. Row spacing is critical in figuring the proper amount of the pesticide to use. A three-foot row spacing, for example, will have about 15,000 row feet per acre. A six-foot row spacing, by comparison, has about 7,200 row feet per acre.
“It is very important to remember to not follow up an injection of a neonicotinoid with a foliar application from the same family. If you get white flies in a field that has been treated with injected Admire, or a similar neonicotinoid insecticide, you could be setting yourself up for resistance problems by coming back later in the season with a foliar application of the same family of materials,” Smith says.
He also says that injecting a neonicotinoid immediately after planting isn’t a good idea, because the plant’s root system isn’t developed enough to absorb the insecticide. A better bet is to wait 7-10 days after the transplants are set before injecting Admire, or any other neonicotinoid.
The test plot of pumpkins at the Edisto Station was planted July 1 and Admire was injected on July 8. Under plastic, with good moisture and high temperatures the root systems will develop quickly and should be able to absorb most of the injected pesticide, Smith says.
By waiting, the plants develop a better root system and they will make better use of the injected materials. By waiting, the grower will also get better use of his crop protection dollars, Smith explains.
Miller notes the pumpkins used in the irrigation study are genetically modified, with resistance to the four major viruses that attack pumpkins. He encourages growers to attend Edisto’s fall field day at which time the genetically altered pumpkins will be discussed further.