Pesticide Use by the Numbers 1.9 million lbs North Dakota uses the most total fungicides on potatoes each year 662,000 lbs Idaho uses the most total herbicides on potatoes each year 205,000 lbs Washington uses the most total insecticides on potatoes each year 82%of growers use insecticides 94%of growers use 97%of growers use herbicides fungicides Six benefi ts of Serifel biofungicide ® Research suggests Serifel biofungicide can reduce resistant populations of diseases when used in combination with conventional chemistries such as Priaxor® Serifel biofungicide has no maximum residue limit (MRL) and a four-hour re-entry interval. fungicide and Endura® fungicide to actually work better. 10 Spudman Serifel biofungicide has 1 trillion more spores per application per acre than most other competitors' biologicals on the market. Biofungicides can help reduce the damage caused by diseases. Biofungicides work by colonizing the surface of roots or plants with benefi cial bacteria that suppress disease development.