How to Stop Grasshoppers Eating Lettuce: Barriers, Timing and Natural Enemies

ByKen

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Learning how to stop grasshoppers eating lettuce means understanding when the insects are most vulnerable and where they come from. Lettuce is one of the vegetables grasshoppers prefer, and both extension sources reviewed here list it among the crops most often damaged. Colorado State University Extension and the University of Arizona Cooperative Extension describe the same basic pattern: grasshoppers lay eggs in soil, the young hatch in spring, and the nymphs feed on tender foliage. Their guidance centers on timing, physical barriers, and the insects’ natural enemies.

Quick answer

  • Note the setting. The Arizona guide says gardens and landscapes next to open grasslands or shrublands often receive the highest impact.
  • Cover young lettuce with lightweight spun fabric, sometimes called Remay or frost cloth, which allows light and some air circulation.
  • Watch for nymphs in late spring, when the first days after hatching are critical to their survival.
  • Leave natural enemies in place. Birds, robber flies, and some predators feed on grasshoppers.

Why lettuce gets chewed

Grasshoppers are not equally interested in every garden plant. The Colorado State guide says certain vegetable crops are favored, including lettuce, carrots, beans, sweet corn, and onions. Squash, peas, and tomatoes, measured by their leaves rather than their fruit, are plants that tend to be avoided. Lettuce is therefore one of the crops to protect first in a mixed garden. The Arizona guide makes a similar point: when grasshoppers can reach novel plants, they may eat them preferentially, and many annual flowers and vegetables are in that group.

Location matters as much as crop choice. The Arizona guide says gardens and landscapes that receive the highest impact are often adjacent to open grasslands or shrublands. The guide does not say how far a bed must be from grassland to avoid damage, so the location point is a pattern to watch rather than a rule.

Recognizing the stages

The Colorado State guide explains the life cycle in useful detail. All grasshoppers lay their eggs in soil, in the form of tight clustered pods, and relatively dry soils that are undisturbed by tillage or irrigation are preferred. Egg-laying can concentrate at certain sites with favorable soil texture, slope, and orientation, which produces what the guide calls egg beds. Most species overwinter as eggs. For most species, the eggs hatch in mid- to late spring, depending on soil temperature.

After hatching, the tiny first-stage nymphs move to the surface and seek tender foliage to eat. The guide says the first few days are critical to survival, and that adverse weather or a lack of suitable food can cause high mortality. Surviving grasshoppers usually molt through five or six stages before reaching adult form. The Arizona guide adds a practical identification point: nymphs do not have mature wings but may have wing buds, and they cannot fly. Adults have fully developed wings, and many species fly well.

This is why early-season scouting is useful. A gardener who sees small, wingless grasshoppers on lettuce in spring is looking at the stage both sources describe as most vulnerable. Once the insects are adults and migrating, the options narrow.

Physical barriers: spun fabric and row covers

The Arizona guide says home gardeners may want to consider a physical barrier made of lightweight, spun fabrics, also called Remay or frost cloth. These fabrics are often used for floating row covers. They allow light penetration and some air circulation, and they can be found at garden centers and through mail-order catalogs. The guide’s wording is direct, so a cover placed over young lettuce is a reasonable first step for a small bed.

Barriers have limits. The Arizona guide notes that under severe circumstances, grasshoppers may start to feed on the fabric. The guides do not give a measured effectiveness figure for row covers in home gardens, so treat the cover as one layer rather than a complete solution.

Natural enemies and wildlife

Both sources describe natural controls that gardeners can encourage. The Colorado State guide says some insects commonly feed on grasshoppers, including blister beetles and robber flies. It also says many birds, notably horned larks and kestrels, feed heavily on grasshoppers. The Arizona guide adds that spiders, wasps, robber flies, rodents, and birds eat nymphs and adults, and it notes that small wasps of the family Mymaridae parasitize grasshopper eggs.

Weather is also a natural control. The Colorado State guide says cold, wet weather is very destructive to newly hatched grasshoppers. It adds that very dry winter and spring conditions can also be harmful because tender new growth is not available. The Arizona guide says the sheer numbers of grasshoppers can make management challenging, even with natural controls in place.

Some natural enemies are fungal or nematode-based. The Colorado State guide describes a fungus that makes infected grasshoppers climb plants before they die, and a large nematode that sometimes develops inside them. The guide says wet weather favors both. Because these agents occur naturally, a garden that already has birds and predators may have some built-in pressure on grasshopper numbers.

Timing your watch

The Colorado State guide says that early-season surveys are useful for anticipating problems. Late-summer and early-fall grasshopper counts can indicate problems the following year, and follow-up surveys the next spring can show when eggs have hatched. For a home gardener, a practical version is to note where grasshoppers were numerous the previous year, and to check those areas in late spring for the small nymphs the sources describe.

The Arizona guide says that when grasshopper numbers are high and food choices are few, plants can be completely defoliated. Early attention to small nymphs therefore matters more than late attention to a large adult population, which may already be moving to other food.

What the guides say about insecticides

Both sources discuss insecticides and baits. The Colorado State guide describes control programs that use sprays or baits, applied to developing stages. The Arizona guide lists active ingredients labeled for grasshopper control and notes that the label should be consulted before use. This guide does not give product names, application rates, or application steps. If you are considering a product, check current extension guidance for your area and read its label before deciding.

How we chose

We selected two sources that address grasshoppers in gardens directly. The first is a Colorado State University Extension guide titled “Grasshopper Control in Gardens and Small Acreages.” The second is a University of Arizona Cooperative Extension Backyard Gardener publication, number 35, on grasshoppers, adapted from work by Jeff Schalau and dated December 29, 2022. We opened both pages on 2026-10-27 and took every quotation from the retrieved text. We did not use retail pages or product listings.

What we could not verify

Two sources give a solid base, but they are general guides and do not test home-garden methods against each other. We could confirm what each one says. We could not confirm how much a row cover reduces damage in a specific bed, or how a particular lettuce variety compares with others for grasshopper feeding.

What the sources do not say

  • How to measure grasshopper numbers in a home garden, or a damage level that justifies action.
  • The effectiveness of row covers or spun fabric compared with other methods.
  • Which lettuce varieties are least attractive to grasshoppers.
  • How long to keep covers on, or how to time their removal around harvest.

Frequently asked questions

Do grasshoppers eat lettuce more than other garden crops?

The Colorado State guide lists lettuce among the vegetables that grasshoppers favor, along with carrots, beans, sweet corn, and onions. Squash, peas, and tomato leaves tend to be avoided.

Can I use row cover to protect lettuce from grasshoppers?

The Arizona guide suggests lightweight spun fabric for home gardens, and notes it is often used for floating row covers. It also warns that grasshoppers may feed on the fabric under severe conditions.

When should I start watching for grasshoppers?

The Colorado State guide says problems tend to increase beginning in early summer and can persist until hard frosts. It also says the first few days after hatching in spring are critical, so checking for small nymphs in late spring is a useful start.

Do birds help control grasshoppers?

Yes, according to both sources. The Colorado State guide says many birds, notably horned larks and kestrels, feed heavily on grasshoppers, and the Arizona guide lists birds among the animals that eat nymphs and adults.

Should I spray lettuce with an insecticide?

This guide does not recommend a product or method. Both sources discuss insecticides, and the Arizona guide says the label should be consulted before use. Check current extension guidance for your area before deciding.

Related reading on this site: how to grow lettuce in pots and how to prevent lettuce from bolting.

Sources

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