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Common Vegetable Problems

Every region has their own set of garden challenges, we just seem to have a few more than most places in California.

While not comprehensive, this page has information on the most common issues we see in the Eastern Sierra in vegetable gardens and provides advice or a link when possible.


No place is immune to invasions of insect pests. Even our remote location has a bounty of arthropods ready to eat your veggies. Here are the most common pests.

Aphids: Since you garden is often an oasis of green in an otherwise brown desert, we are prone to huge aphid outbreaks. These seem to be worst in spring. The link above provides some control options. Since this problem is worse in spring, quick control is usually effective. Start by blasting the aphids off if the plants are large enough to handle a strong stream of water. Most gardeners fail to notice their problem is an insect. Instead they see pale, curled leaves. Be sure to uncurl a few leaves to determine if you have aphids or another problem. 

Squash Bugs: If you grow squash or melons, you are familiar with this pest. UC IPM has some control information.  Most local gardeners have little success with insecticides for control. We recommend removing the eggs and insects as soon as you see them. Some people vacuum them. Removing plant debris helps. Newspaper or boards laid out at night are a way you can trap them if you check early in the morning. Knocking the insects into soapy water is a good way to kill them. Butternut, Royal Acorn, and Sweet Cheese are somewhat resistant to squash bug feeding. Yellow crookneck and zucchini seem to be extremely susceptible to their feeding.

Earwigs: In most places these are minor pests that cause little damage. In our area they can be devastating to seedlings and plants in containers. Trapping earwigs is a good way to start controlling them. A low-sided can, such as a cat food or tuna fish can, with 1/2 inch of oil in the bottom makes an excellent trap. Fish oil such as tuna fish oil is very attractive to earwigs, or vegetable oil with a drop of bacon grease can be used. These traps are most effective if sunk into the ground so the top of the can is at soil level. Mulches can harbor earwigs, so if you have a problem, discontinue their use on those crops affected. It is common in our area to require chemical control. Since recommendations change often: consult this page for up-to-date pesticides you can use for earwigs.

Tomato Horn Worm: The larvae of this insect is a kind of sphinx moth. These caterpillars love to eat tomato fruit. They are green in color and are actually very difficult to see on the vines, especially when small. The best control is to keep your eyes open for them and remove them from the vines. You can squish them or drop them into soapy water. (The tomato fruitworm is not much of a pest in our area, but it is here. Hornworms are the main pest in gardens on tomato fruit.)

Stink Bugs: We have a lot of species of stink bugs in our area. Some are only found here in the desert. For the same reason we have aphid problems, we get stink bugs: gardens act like an oasis and they come in. UC IPM has a page about stink bugs in general. We have a different species of Chlorochroa here but otherwise have all those pests in our area. Like squash bugs, the best solution on garden vegetables is to remove them mechanically from plants.


Our dry climate makes it hard for many species of fungal pathogens to survive. We do have some common disease issues on vegetables, just not very many. But what we do get can be devastating!


We only widely see one fungal disease: early blight on tomatoes (Alternaria solani). This disease causes leaf spots. It usually begins from the bottom up. We only see this on wet springs and possibly during a very humid monsoon season. Since dry weather is usually just around the corner here, removing the sick leaves usually does the trick. Sprays are seldom needed.

It's not truly a fungus, just usually grouped with them, but many vegetables have issues with Phytophthorarots. Peppers planted too early are often affected. Anything over-watered can have problems with this as well. Plant at the right time and do not overwater and you will probably not have an issue. 

There are other fungi we have to deal with, but they are less common. Contact us if you have questions.


We have more problems with viruses than fungi. Tomatoes and summer squash are the most commonly affect plants. 

On tomatoes and peppers we see Tobacco Mosaic Virus, Beet Curly Top Virus, and Tomato Spotted Wilt Virus. 


Here is a 24-minute video about these diseases:

There are a number of viruses that affect melons and squash. The good resource on identifying them is at this page


knobby roots of a tomato infested by root knot nematodes
knobby roots of a tomato infested by root knot nematodes
If you share plants with others or use tools at more than one location, you may end up with an infestation of Root Knot Nematodes. Nematodes are tiny little worms that can have a big impact in the garden.  Root knot nematodes affect many crops. They cause knobby, malformed roots and will usually affect yield. 

Gardeners usually encounter these after they bring them into their garden by mistake. Always clean and sanitize equipment that goes to many sites. Don't spread this and you should have little problem.

Nematode management is a complex topic. I encourage you to look at this UC Pest Note for more information. There are some resistant varieties you can plant.

Environmental Problems

Our climate causes its own problems. Obviously the hot/dry/cold/windy issues will create a multitude of problems, but these are usually clear. 

Here are some more subtle problems related to our climate:

Cool soil — the air temperature may be fine for growing but sometimes the soil is not warm enough. They can cause problems on beans, peppers, melons, and okra. Plant these when the soil is definitely warm.

Poor Fruit Set — Tomatoes (especially names you recognize) may fail to set fruit during the heat. High temperatures and low humidity make pollination fail. This is also common on green/wax beans. The solution is to try a different variety next year. There are many heat-set tomatoes on the market to gardeners, and cherry/grape tomatoes are less bothered by the heat. Bonnie Plants has a good page on growing tomatoes in hot weather. Preliminary research suggests that growing peppers and eggplants under a light shade cloth (30-40%) will increase fruit set. We have tried red and black shade cloth. Both worked.

Bolting of Greens and Cole Crops — Various cool-season crops like lettuce and broccoli will send up flowers prematurely when temperatures get to high. This is called bolting. It usually ends your season. Try using shade cloth to maintain cooler temperatures.

Onion Flowering and Bulbing — Onions and their kin will start to flower with wide fluctuations in temperatures. Although safe to eat, the onion bulbs will not grow any more and storage will be affected. Daylength can affect bulb formation as well. In our area we should grow intermediate day onions.