1) In cabbage family crops (broccoli, cauliflower, cabbage, Brussels sprouts etc.) we use B.t. (Bacillus thuringiensis), an organic spray, for the control of Cabbage Worms.
2) Potatoes: The biggest problem is with Colorado Potato Beetles, Entrust, an organic spray, to control them. However, usually once a year one application of a synthetic pyrethroid is needed to control Potato Leaf Hoppers.
Late Blight (of the Irish Potato Famine fame) has been very destructive in the last 3 or4 years. Starting in 2013 we have been applying 2 sprays, Ridomil Gold and Tanos. They are very expensive, but are much less toxic than most organic sprays.
Most conventional potatoes get 6 to 12 sprays not approved for organic production. Our potatoes only get 1, or perhaps in a late blight year, 2 such sprays.
3) Eggplant is the absolute favorite food of Colorado Potato Beetles and the plants are very sensitive to their damage. For this reason it is occasionally necessary to use something stronger than B.t. like a synthetic pyrethroid for their control.
4) Zucchini, Summer Squash and Cucumbers: The early plantings (harvested through August 15th) usually manage with 1or 2 applications of Kaolin Clay "Surround" (organic) But occasionally they require 1 or 2 applications of a synthetic pyrethroid to control the striped cucumber beetles. This is never applied with fruit present, and is never applied to late plantings (Harvested after August 15th).
5) Tomatoes are now No Spray. We used to have to make several applications of cupric hydroxide (organic spray) to help control leaf diseases. Now we just keep them dry in an unheated greenhouse.
6) Carrots routinely get a herbicide spray of Linuron to control weeds. This is applied at least 2 months before the start of harvest.
Our carrots get only 1 herbicide spray. Most conventional carrots receive 4 to 6 sprays that are not approved for organic production.
7) Our Strawberries are sprayed 1 time with Malathion to control Tarnished Plant Bugs (TPB). The plants get sprayed just as the first blossoms start to open. The fruit themselves never get sprayed at all.
The TPB attacks the blossoms and cause the fruit to develop poorly. Fruit from damaged blossoms are small, have a hard knob at the point, and a bitter taste. The plants get sprayed just as the first blossoms are opening, so that there are no TPB around during the bloom period.
8) Since 1992 we have grown Sweet Corn almost entirely without sprays. Very rarely, perhaps once every 2 or 3 years, we have to save a planting of sweet corn that would otherwise have been lost to weeds, by spraying with Atrazine.
9) The onions, like the carrots, get a routine herbicide spray. The herbicide used on the onions is of Oxyflorfen This is applied at least 2 months before the start of harvest.
10) Summer Squash is prone to Scab if the weather is cool and wet as many Vermont summers are. When this is the case we spray the summer squash with Clorothalonyl.