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Managing Pests in the Vegetable Garden

Managing Pests in the Vegetable Garden

Photo UF/IFAS Pinellas County Extension Urban Vegetable Demonstration Garden

by: Theresa Badurek, UF/IFAS Urban Horticulture Extension Agent, Pinellas County

Growing your own vegetables is a fun way to eat healthy and be more active.  If you grow enough you can even save some money on your grocery bill!  Florida is a great place to grow your own food because with our warmer temperatures you can garden just about year-round.  However, the same warm climate and great growing conditions can contribute to a host of vegetable garden pests.  Some pests seem to pop up at random while others seem to show up time and again as if on schedule.  To complicate matters there are also plenty of good bugs at work in the garden that you will want to protect.  What’s a Florida gardener to do?

Just like a great garden takes planning and preparation, a productive garden also needs an insect management program.  This program should include scouting your garden for problems early on- when it is easier to tackle them.  So, what should you be looking for?  You must know how to tell if a pest is harmful, helpful, or harmless before you react.  There are pests that attack roots, stems, leaves, flowers, and fruits, and they might show up at any stage of growth, from seedling to mature plant.  We will discuss these “bad” pest bugs according to the part of the plant that they attack.  Then we’ll talk about how to fight back!

Attack from below!

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Granulate cutworm, Photo by John Capinera, UF Entomology and Nematology Department

Gardens in areas that used to be covered by turfgrass are especially susceptible to these soil dwelling insects.  It is recommended that a new plot in that kind of space be thoroughly tilled and kept clean and free of grass for 30 or more days before planting.  For some of these pests, the addition of organic matter to the soil along with regular irrigation can also help.  The common pests that live in our garden soil are: wireworms, cutworms, mole crickets, grubs, and lesser cornstalk borers.

Leaf and stem chewers

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Caterpillars are the major suspects here- and they can do a lot of damage if left unchecked.  Many of the caterpillars you find in your garden can be hand-picked and drowned in soapy water or squished- depending on your preference.  Armyworms can be reduced by planting crops like corn, beans, peas, potatoes, and tomatoes as early in the spring as possible.  If a caterpillar problem gets out of hand you can use Bt (Bacillus thuringiensis), which is a bacteria that kills caterpillars but is safe for people and even other “good” bugs.  Beetles can be hand-picked and destroyed, but you may need to do this continuously throughout the growing season.  Common leaf and stem chewers include: armyworms, cabbage loopers, tomato hornworms, bean leafrollers, beetles, and leafminers.

Plant vampires!

Green peach aphid, Photo UF/IFAS

Green peach aphid, Photo UF/IFAS

These garden pests have specialized mouthparts that they insert into the plant to suck out plant sap.  In addition to reducing the vigor of your plants and generally stressing them out, some of these pests can even transmit plant viruses from one plant to the next as they feed.  Some even inject toxins into the plants that can cause abnormal or distorted growth.  Aphids and spider mites can often be controlled with a squirt of water from the garden hose.  If you encounter severe infestations of these plant sucking pests you may need to use an insecticide such as horticultural oils and soaps.  .  Take care when using these as they will kill even the “good” bugs.  Handpicking and destroying stinkbugs and leaffooted plant bugs may offer enough control if routinely done but an insecticide may be needed for a severe infestation.  Use only in targeted areas where the infestation exists.  Plant vampires you may find in your garden include: aphids, leafhoppers, stinkbugs, leaffooted plant bugs, thrips, spider mites, and silverleaf whitefly.

Fruit and seed feeders

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Mature pickleworm larva, Diaphania nitidalis (Stoll), feeding on blossom. Photograph by John L. Capinera, University of Florida.

We’ve saved the most potentially damaging group of pests for last.  These buggers go after your harvest!  In some cases planting early and harvesting as soon as you can will go a long way in preventing damage.  For most pests in this category prevention is the most important tool- as the damage they do directly impacts your precious vegetables.  Many of them are caterpillars that can be controlled using Bt mentioned in the leaf chewing pest section above.  To be effective this must be done early and often- when blossoms first appear.   Some fruit and seed feeders that may be a problem in your Florida garden may include: corn earworms, pickleworms, cowpea curculios, pepper weevils, potato tuberworms, and stinkbugs.

Pest Management Tips for any Florida Garden

  • Rotate crops each season.
  • Till or plow the soil long before planting- and keep it free of weeds.
  • Add organic matter such as compost or composted manures to your garden.
  • Buy only insect, disease, and weed free transplants.
  • Water and fertilize appropriately- too little water can stress plants and too much fertilizer can encourage pests.
  • Monitor the garden daily or at least twice a week to catch problems early.
  • Learn the “good” bugs and protect them.
  • If you must treat with chemicals- even organic ones- spot treat only affected areas.
  • Harvest crops as soon as they are ripe.
  • Remove plants once they are no longer producing- or cut them down and plow them into the soil at the end of the season.

For information on protecting bees from pesticides:

For a full UF/IFAS Fact Sheet on the topic, including specific control measures and images of each pest:

Happy gardening- don’t forget to scout for those pests!