Preventative Treatments

Corn

  • Corn Ear Worm (CRW) [From Utah State Univ] In corn, good control is dependent on applying insecticides before larvae enter the ears. Start spraying within 2 days of the beginning of silking, or as indicated by trap counts. About half of the eggs are laid within 2 days of silk emergence, and the remainder of the eggs are laid by 9 days later. Reapply insecticides to keep an active residue on new silk. Silk grows about 1/2 inch per day. Once silks turn brown they are no longer attractive as egg-laying sites. Reapply insecticides using the suggested intervals (2-5 days) while silks are still actively growing. Stop sprays when silks turn brown. Recommended chemicals:
    • Bacillus thuringiensis (Dipel, Thuricide, others) – not effective on moths, must be ingested by larvae; effective in tomato and pepper if reapplied every 2 to 3 days; not effective in corn
    • bifenthrin (Brigade)R
    • carbaryl (Sevin)H – toxic to bees; Sevin XLR formulation is less toxic than others
    • cyfluthrin (Baythroid)
    • esfenvalerate (Asana)
    • horticultural mineral oil (many brands)H,O – suffocate eggs on silks, must reapply every 2 to 3 days for suppression only
    • lambda-cyhalothrin (Warrior)
    • malathion (Malathion)
    • methomyl (Lannate)
    • permethrin (Ambush, Pounce)
    • spinosad (Spintor, Success, EntrustO) – effective upon ingestion by larvae, but no contact activity; effective for tomato and pepper, but not corn
    • thiodicarb (Larvin)
    • zeta-cypermethrin (Mustang)

Onions

From Dixondale Farms – We have several fungicide options that we recommend. Mancozeb Fungicide with Zinc and OxiDate Organic Fungicide. Both of these products keep disease out of the foliage during the growing stages and will also help prevent any diseases that will cause rotting in storage ensuring your onions store to their maximum potential. To keep your onions disease free, we suggest putting your onions on a bi-weekly preventive treatment plan. If you notice early signs of disease, these products can be used weekly as needed.

Summer Squash

From Iowa State University Extension and Outreach

  • Preventing squash vine borer damage usually requires treating the base of the plants with a residual insecticide spray at the time the moths are flying (early to mid June). Sprays provide a much better barrier against borer attacks than do dusts. Home gardeners can apply Sevin, permethrin, bifenthrin, esfenvalerate, spinosad or other labeled home garden insecticide.  From here. The following, from the same site, is a bit different and from a different page. Treating the base of the plants with either malathion or rotenone works to control borers before they enter the stems not after the fact. 
  • Idea – Use malathion until blooming, then Spinosad.

Tomatoes

  • From IFAS Disease Control for Florida Tomatoes:
    • A systemic insecticide, imidacloprid, can be applied prior to planting and provides good early season control of silverleaf whitefly to prevent it from spreading the major virus problems identified as tomato yellow leaf curl virus (TYLCV) and tomato mottle virus. These viruses are transmitted to healthy plants by the silverleaf whitefly. 
    • Copper and mancozeb are recommended for bacterial spot control. When the weather conditions favor bacterial spot, growers may have to use this tank mix as their primary “fungicide.” Additionally, the systemic acquired resistance inducer, acibenzolar-S-methyl, assists with reducing bacterial spot severity. 

Citrus, shrubs, camellias, and deciduous fruit trees Shrubs

  • Control persistent scale insects on citrus, shrubs, camellias, and deciduous fruit trees; apply horticultural oil while plants are dormanthttp://edis.ifas.ufl.edu/ep451
  • Homemade Dormant Oil Spray for Fruit Trees – Includes Dormant Oil Recipes by Cornell
  • Peach Trees – Peach trees are also susceptible to a primary disease called peach leaf curl, which is caused by the fungal pathogen Taphrina deformans. This disease causes uncharacteristic redness in newly emerging leaves, and it prevents them from developing properly. Copper compound sprays, such as Bordeaux mixture, are applied to peach trees to prevent this disease from developing. If you add 1 percent horticultural oil to a copper spray, the combination helps prevent insect and disease damage to peach trees. Sprays should be applied just after leaf drop in autumn, or just before buds swell in late winter for maximum effectiveness. From SFGate.com.