Imidacloprid labels need to be read closely prior to application
Multiple insecticide products contain the active ingredient imidacloprid, and cherry growers should pay close attention to the label before applying these insecticides close to harvest.
The original imidacloprid trade material labeled for tree fruit use was Provado, but since this patent has expired, the active ingredient, imidacloprid, is now sold under many trade names. Growers need to be sure to thoroughly read the labels of these products for pre-harvest use for four important reasons:
- The pre-harvest intervals (PHI) vary.
- The PHIs vary with the method of insecticide application.
- The use rate is different for different products.
- Tree fruits are not listed on all labels of products that contain imidacloprid.
First, the PHIs of the different products vary, and since this insecticide is often used later in the season, particularly in cherries to target cherry fruit flies, growers need to be sure they are applying these insecticides in accordance with the labeled PHI for each individual product. For example, Admire Pro has a zero-day PHI for stone fruits including peaches, apricots and nectarines, but a seven-day PHI for stone fruits including cherries, plums, plumcos, and prunes. Secondly, the methods of insecticide application have different PHIs. If imidacloprid is soil-applied, which is allowed in stone fruits, the PHI is 21 days rather than seven days when imidacloprid is applied to the foliage.
The third reason to pay close attention to imidacloprid labels is that the different imidacloprid products have different amounts of active ingredient, thus different use rates. Growers should read the label to ensure they are putting out enough of the active ingredient to control the targeted pest. For example, Imidacloprid 2F contains 22.6 percent of the active ingredient imidacloprid while Admire Pro contains 42.8 percent imidacloprid. Provado 1.6F contains 17.4 percent imidacloprid and the Provado Solupak contains 75 percent the active ingredient. Growers will have to know the amount of active ingredient in each product and adjust accordingly to apply at the recommended rate. Too little active ingredient may result in lack of control and potential larvae in fruit.
Lastly, growers need to be aware that some imidacloprid products are not labeled for tree fruits. Imidacloprid 4F (EPA #: 66222-156) is labeled primarily for cotton, according to CDMS.net. We could have an incident where a grower applies this product for cherry fruit fly control, likely not realizing this particular imidacloprid product is not labeled in cherries. Unfortunately, because cherries are not on the label for this specific product, it is technically illegal to use this product in cherries. However, in terms of residue testing for maximum residue limits, the detections would only show the active ingredient, not the formulation.
Michigan State University Extension’s recommendation to read labels before a pesticide application is not new, but with so many products on the market with similar names and active ingredients, reading those labels is more important than ever.