It's July and the tomatoes in your garden are finally starting to ripen. One afternoon you notice the first ripe one is nearly ready to be picked. The next afternoon, you head out to harvest the tomato and find it on the ground looking like this one: 

Photo credit: B.Messenger-Sikes

After you get over groaning about the loss of your first ripe tomato of the season, you may wonder, “What critter ate my tomato? And what can I do to stop it?” Here are some tips to answer those questions.

Many home gardeners love eating garden-fresh tomatoes. Unfortunately, many pests also love to share in the bounty of vine-ripened tomatoes. Known nibblers on home-grown tomatoes include birds, rabbits, squirrels (both ground and tree), rats, hornworms, and even slugs and snails.

Start by doing some detective work to figure out likely suspects. In this case, the half-eaten tomato was on the ground near the plant. That fact narrows the list of possible pests. It's not a hornworm, slug or snail which had no means or incentive to remove the tomato from the plant. Also, it is probably not a bird which would more likely peck on the tomato while it remains attached to the plant. So, we're left with rabbits, squirrels and rats as the leading suspects of interest.

Can you narrow the list further? Unless you live near an open space area where you've seen ground squirrels foraging near their burrows, you may also be able to eliminate that suspect as well. If you have the misfortune of trying to grow a garden close to ground squirrel territory, it would be unlikely that one missing tomato would be your first experience with the critter in your garden. Hopefully, you're already familiar with the University of California's recommendations for managing the pest. If not, you can find UC's recommendations here: https://ipm.ucanr.edu/home-and-landscape/ground-squirrel/pest-notes/?src=302-www&fr=3777 We'll assume for this blog post that we can rule out the ground squirrel.

Likewise, you may be able to rule out rabbits if they don't live anywhere near your garden. If you do live near rabbits, it would also be unlikely that your first encounter with rabbit damage to your garden would be one missing tomato. A rabbit's diet preference is for succulent, green vegetation, with grasses and herbaceous plants making up the bulk of the diet. If rabbits are in your neighborhood, UC has very good suggestions for building a fence to exclude them from your garden: https://ipm.ucanr.edu/home-and-landscape/rabbits/pest-notes/?src=302-www&fr=3783 So, we'll also eliminate rabbits from the suspects list.

Now we're left with tree squirrels and rats as our leading suspects. Both pests love to eat tomatoes—particularly just as they are ripening. Maybe you've never seen a rat in your yard or neighborhood but frequently see squirrels. Don't assume that fact means that the squirrel is the top suspect. People don't often see rats, but most of us with gardens probably have them living nearby.

A good way to know whether a rat or a squirrel caused the damage is to figure out the time of day when tomato raids occur. In this case, you visited your garden on two successive afternoons so there is no way to know for sure what time the tomato was stolen. But the culprit is almost certain to visit your garden again as more tomatoes ripen. Get in the habit of taking a walk in your garden in the evening and again early the next morning. Squirrels are active only during the daytime and rats are mainly active at night. So, if you notice a tomato that looked fine on your evening garden visit is missing or partially eaten when you visit in the morning, you know the culprit and it's time to arrest the rat. And vice versa, when the tomato raid occurs in the daytime, a squirrel is the prime suspect.

If you decide the culprit is a rat, my recommendation is that you start setting some snap traps to kill them. This UC blog post has good instructions for trapping with an easy to set snap trap: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=39179?src=blog43296. Be sure to take note of the blog's suggestion to bait the traps without setting them until the bait has disappeared a couple of times. Rats are very wary of new objects and will avoid them. If a rat visits an unset trap and safely eats the bait a couple of times, you're more likely to catch the rat once you start arming the trap.

If you trap a rat in your garden, you might want to do some further investigation to find where they are nesting. This UC website warns: “Once rats have invaded your garden or landscaping, unless your house is truly rodent proof, it is only a matter of time before you find evidence of them indoors.” https://ipm.ucanr.edu/home-and-landscape/rats/pest-notes/ The website also provides good directions on steps to take to make your house rat proof.

Finally, we come to the tree squirrel as the culprit—the toughest nut to crack. If you do an internet search for “how to keep squirrels from eating my tomatoes”, you'll find many sites that recommend using plant or chemical repellents with smells that squirrels don't like. The effectiveness of such repellants is questionable. Likewise, while frightening devices may work initially to keep a squirrel away, the squirrel will soon get used to it and start ignoring the device.

Live-kill squirrel traps are available, but they are much more challenging to set up and use successfully than the easily set snap traps used for rats. And some folks who are willing to kill rats may not feel the same way about killing a squirrel. Live trapping squirrels is also possible, but it is illegal to move a trapped squirrel to a new location. Squirrels trapped in a live trap must be humanely euthanized by gassing with carbon dioxide or shooting. Even if you are successful in eliminating a squirrel that was eating your tomatoes, chances are good that another squirrel will soon take over the territory and won't ignore your garden for long.

To protect a tomato plant from squirrels, consider building a cage around the entire plant using hardware cloth or chicken wire topped with plastic bird netting to exclude the squirrels from reaching the tomatoes. It may keep the squirrel out, but it will take some effort to build and will make it difficult to care for the plant and harvest ripe tomatoes.

To read UC's suggestions for managing squirrels, check out this website: https://ipm.ucanr.edu/home-and-landscape/tree-squirrels/pest-notes/?src=302-www&fr=3788

Here are a few more photos of nibbled tomatoes with links to the UC websites that tell you how to manage the culprits:

Hornworm damage to tomatoes

UC website: https://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/hornworm.html 

Snail damage to tomatoes. UC Website:

UC Website: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7427.html 

CC license reference.DebRoby CCPDM1.0

Bird damage to tomato. UC website: https://ipm.ucanr.edu/home-and-landscape/birds/pest-notes/

Help Desk of the UC Master Gardeners of Contra Costa County (TKL)

Have you noticed tomatoes that have round, water-soaked spots on the bottom? Blossom end rot (BER) is a frustrating problem that can be quite common in vegetable gardens, as it can affect tomatoes, peppers, and squash. You might notice it after a few very hot days. It usually starts on green fruit as a small, discolored spot on the end opposite the stem that might look water soaked. The spot enlarges and tissues dry out, becoming sunken, collapsed, and leathery.

Some tomato varieties, especially paste tomatoes, are affected more than others, but all varieties except cherry tomatoes seem to be susceptible if conditions are conducive. It is more likely to occur earlier in the season when plants are rapidly growing, but it can also show up later in the season when we have hot, dry weather.

Blossom end rot results from a low level of calcium in the fruit and a lack of water balance in the plant. Most of our soils have plenty of available calcium so there is no need to add more. Fluctuations in irrigation and/or heavy application of nitrogen are often the culprits in this condition. To reduce blossom end rot, monitor soil moisture to make sure the root zone neither dries out nor remains saturated. Follow recommended rates for vegetable fertilizers, using organic fertilizers.

Improvement in irrigation practices usually results in the problem going away. Rather than watering on a schedule, you should check the soil to determine its moisture level. Either by digging down into the soil without disturbing the roots or using a moisture meter, check to make sure the entire root zone is moist but not soggy. Use mulch around the plants to help maintain soil moisture, but make sure the mulch isn't right against the base of the plants.

Blossom end rot is not caused by a pathogen, so there are no pesticide solutions.

To reduce blossom-end rot:
• Use cover crops in the off season to increase water-holding organic matter in the soil.
• Irrigate before periods of hot weather.
• Don't disturb the root area.
• Don't over fertilize. Too much nitrogen during the early fruiting period can tie up calcium and make BER worse. Manure, especially poultry manure, can make it worse.

Vegetables affected by blossom end rot are still edible if they haven't begun to get moldy. Just cut away the discolored area.

More information about blossom end rot:
http://ipm.ucanr.edu/PMG/GARDEN/VEGES/ENVIRON/blossomendrot.html

Information about growing tomatoes in the home garden: https://anrcatalog.ucanr.edu/pdf/8159.pdf

Help Desk of the UC Master Gardeners of Contra Costa County (SEH)

According to someone who knows such things, grapes are one of the most widely cultivated fruit crops in the world. Worldwide, there are over 10,000 different varieties, and whether one's interest is ambience, erosion control, raisins, jelly, table munchies, or wine, grapes nicely fit the bill. While grapevines are relatively hardy, they still need year-round care to be most productive.

There are extensive data regarding the growth and maintenance of grapes. Specific recommendations for when/where/how and why will depend upon some critical factors like soil type, location, sun exposure, grape variety, and more.

There are a few generalities that are helpful to home gardeners wanting grapes to be an integral part of their garden landscape.

• First, grapes need sun, full sun if possible, because less light results in lower fruit production, poorer fruit quality, and an increased incidence of certain diseases like powdery mildew.
• Second, grapevines can thrive in a variety of soil types, but good drainage is critical. Grape roots can be very extensive and deep, so ideally there should be 3–4 feet of soil above hardpan or rock layers. Table grapes tend to grow quite well on less fertile soils. On poorly drained soil, a large amount of well-decomposed compost should be incorporated before planting.
• Third, grapes need space, the amount of which is dependent upon the desired use of the fruit. Spacing between rows of wine grapes can be as little as 8 feet up to as much as 12 feet in very deep rich soils. Home grapes are often grown on arbors and in that situation one vine would require 50–100 square feet of arbor space. If the interest is only a few grapevines, then a space of at least 3 feet between plants would be a minimal requirement.
• Fourth, water requirements vary as a function of soil type and plant maturity. Water leaches quickly from sandy soils while it tends to collect in heavy clay. New vines should be watered weekly, sufficient to wet the soil 6–10 inches deep. Some recommendations suggest ½–1 inch of water/week for new vines. Five gallons of water spread over a 3' x 3' area is equal to about 1 inch of water. Established vines (over 2 years) can be relatively drought tolerant, but regular watering down to 12 inches will improve productivity. Once vines set fruit, watering can be reduced. Given that water use is so dependent upon a variety of factors like soil type, slope, sun exposure, it is difficult to prescribe a specific water regimen that is applicable to all.

Grapes can be grown from bare root preparations, usually with a fruiting cane grafted onto a disease resistant rootstock; this is probably the safest way to proceed. Alternatively, most grapes can be propagated as ‘own rooted' where a mature cane is simply placed in potting soil. This can be very successful, but the resultant vines are not disease resistant.

Canopy management is extremely important not only for optimization of fruit quality but also for management of potential problems, like powdery mildew. Shoot thinning is done primarily to reduce shoot congestion in the fruiting zone and to adjust flower cluster numbers. In addition to reducing the number of shoots emerging from the crown of the vine, the canes or the spurs, it is also important to strip leaves to increase light and reduce humidity in the fruit zone. However, in areas that can be very hot, it is important that there is adequate leaf coverage over the fruit to reduce sunburn or fruit shrinkage.

Proper pruning is critical to maintain good plant structure, optimize productivity and allow adequate vegetative growth for the following season. Unpruned vines will have excessive numbers of grape clusters and the vine will be unable to ripen the large crop. Pruning is done when the vines are dormant and just before bud break. Mid to late February is a good time in most of Contra Costa County. There are many approaches to pruning which depend, primarily, upon how the grapes are grown. This website has more information about pruning: https://ipm.ucanr.edu/PMG/GARDEN/FRUIT/CULTURAL/grtrainprune.html

Like any plant, there are various types of diseases or conditions that can seriously impact grapevines. Some of the most notorious, such as phylloxera (an aphid-like insect that can destroy roots) or nematodes, can be managed by using disease-resistant rootstock stock. There are many other potentially serious conditions but in the home garden the most likely condition the homeowner will encounter is powdery mildew. This is caused by a fungus that does remarkably well in warm Mediterranean-type climates like ours. The mildew can affect leaves, stems, and fruit and grows on the surface of the affected plant part.

The best management of powdery mildew is prevention, which involves good cultural practices (e.g., canopy management for good air circulation) and, if necessary, fungicide applications. Fungicides can act as protectants, eradicants, or both. Protectants, such as sulfur, prevent new infections from occurring while eradicants like the oils (Neem, Stylet) can control as well as protect against infection. If conditions are right and/or if mildew is detected, protectants and eradicants should be used in 7–10-day intervals. These treatments should not be done when temperatures are near or over 90° F.

There are a number of invertebrate pests that can attack grapes, most notably thrips, leafhoppers, and mealybugs. UCANR has an extensive website that documents the various pests and their control. There are also a number of vertebrate pests that can cause considerable damage to the vines and/or the fruit including birds, raccoons, ground squirrels, gophers, rabbits, and deer. Exclusion techniques (netting, electrical fences, etc.) are the best management techniques for such pests.

For more information about growing grapes, see these websites: https://ipm.ucanr.edu/PMG/GARDEN/FRUIT/grapes.html https://ucanr.edu/sites/gardenweb/Growing_Grapes_in_the_California_Garden/

In spite of the potential problems identified above, grapes are hardy, resilient, and forgiving plants that not only have aesthetic qualities but also provide a wide range of culinary attributes. Give grapes a try—it's worth it.

Help Desk of the UC Master Gardeners of Contra Costa County (JRF)

Photo courtesy of Susan Heckly

When I first started growing tomatoes, I was reluctant and nervous about pruning my tomato plants for fear I would be doing it incorrectly. After 9 years of growing, I have learned that it is one of the best practices to include in your plant care. It is easy to do and produces better tasting and bigger tomatoes because you are helping focus the energy of the plant.

Here are a few simple tips for pruning your indeterminate tomato plants (determinate plants do not need to be pruned):

Removing suckers

• Suckers are the stems/leaves that grow out of the “V” junctions on plants. They grow fast and keep growing all season. These are best snipped off when they are small.
• Pinching can work as well but make sure you don't tear the tender stems. Before removing suckers wait until at least 2 leaves develop and pinch/snip just above that point.

Establishing the leader

• The leader is the main stem of the plant which starts near the ground.
• You may choose to allow additional leaders (or stems) to grow as well. There are advantages for each.
• Plants with two or more stems produce more tomatoes and greater/denser foliage which protects the plants from the sun. Tomatoes can sun burn!
• While the denser leaf canopy may reduce the incidence of black mold and cracking, it may also increase the incidence of other fruit molds such as gray mold.
• Plants with only one leader will bear fruit sooner but will ultimately produce a smaller total crop and may increase the incidence of some diseases due to the lighter foliage.

Topping your plants

• Pruning the top of your tomato plants once they have reached a desired height (usually about 5–6 feet) is perfectly acceptable and will push the energy down into the development of the fruit below.
• I find I need to continually do this all summer.

“Good to know” tips

• DO NOT Prune your plants when they are wet as this could spread diseases.
• DO prune off any bottom branches that are touching the ground as they can provide a direct vector for soil borne diseases to move onto the plant.
• DO prune off any yellowed or discolored leaves later in the season to keep the energy focused on the fruit.
• DO keep your nippers sharp and clean to avoid damaging your plants.

Below is a link to more information about growing and pruning tomatoes from the UC Master Gardener site: 

https://ipm.ucanr.edu/home-and-landscape/tomato/cultural-tips/index.html?src=307-pageViewHLS#:~:text=Pruning%20tomato,-Pruning%20is%20not&text=Plants%20with%20two%20or%20more,the%20others%20as%20they%20develop.

Happy Growing!

Help Desk of the UC Master Gardeners of Contra Costa County (PDS)