From the UC Blogosphere...
Bees are known to prefer yellow and blue flowers, but pink suits them just fine, too. Here's proof: Two honey bees...
By Lee Oliphant UCCE Master Gardener
I carefully selected disease resistant tomato plants this year and they look healthy. But something is chewing on leaves and fruit. What is it, and what can I do about it? Katie, Cambria.
It is difficult to know what is doing damage to your tomato plants unless you catch the pesky critter in the act. Some damaging invertebrates include sucking insects such as aphids, thrips, whiteflies, and tomato russet mites. When there is evidence of chewing as you describe, it is most likely caused by flea beetles, loopers, or the westerns spotted cucumber beetle. Hornworm and the tomato fruitworm can damage both leaves and fruits. Snails and slugs also dine on tomato plants and fruits. Be observant during the daytime and use a flashlight in the evening to try to identify the culprit.
The University of California lists over 20 invertebrates that feed on tomato leaves and fruits on the UC Integrated Pest Management (IPM) website: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/tomato.html. The site describes each insect, its eating pattern, and how you can safely manage it in your garden.
Most authorities do not recommend spraying insecticides in home vegetable gardens. Insects can be hand-picked from the leaves and put in a bucket of soapy water. Hornworms, a common pest of tomato plants, are large green caterpillars with a rear prong that looks like a horn. They are the larvae of the sphinx moth, a nighttime pollinator. Tomato fruitworms are small green or brown-striped caterpillars that eat the leaves and the fruit of tomatoes. You may also have seen them inside the husks of corn, dining on tender kernels.
Practice good IPM methods of control and you'll have few problems with pests on tomatoes. Let predators, parasites, pathogens, and competitors control pests. Reduce pest establishment, reproduction, and dispersal through good gardening practices like keeping your garden clean. When possible, use traps (like yellow sticky strips), instead of sprays. Pesticides are recommended only when needed and in combination with other approaches for more effective, long-term control. Pesticides should be selected and applied carefully and in a way that minimizes their possible harm to people, non-target organisms, and the environment. Regardless of unwelcome visitors, home-grown tomatoes are worth the effort!
Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Help Desk Response (via email after phone conversation followup to original email request) Thank you for contacting the UC Master Gardener Help Desk. It was nice to speak with you about your unidentified plant with “black stuff” on the leaves. As we discussed, your plants have sooty mold covering the tops of the leaves. It's growing on the honeydew that was excreted by insects living under the leaves above. From your description, those insects are most likely scales of some kind.
The sooty mold is really no problem for the plant, except in extreme cases where it blocks the sun and stops photosynthesis. It won't spread to other plants that don't have honeydew on them. Here's a link to more information about it: http://ipm.ucanr.edu/PMG/PESTNOTES/pn74108.html.
Many species are well controlled by natural enemies, but ants can protect the scales against the predators, so take measures to control the ants. Spraying horticultural oil during the dormant season or early summer when crawlers are moving may be all the treatment you need.
Information about scales and their control: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html and
Information about ants and their control: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7411.html
Please let us know if you have more questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925)646-6586, email: firstname.lastname@example.org, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (http://ucanr.edu/blogs/CCMGBlog/).
The 10th annual National Pollinator Week ends Sunday, June 25, and what an opportunity it's been to showcase our...
Pollinator Week, June 19–25, 2017: Bee Knowledgeable!
—Stephanie Parreira, UC Statewide IPM Program
Bees are the most important pollinators of California agriculture—helping us grow field crops, fruits, nuts, and vegetables. Honey bees receive most of the credit for crop pollination, but many other kinds of bees play an important role as well. There are 1600 species of bees in California! Take time during Pollinator Week to learn about the different kinds of bees and what you can do to help them flourish.
Why should I care about other kinds of bees?
Bees other than honey bees contribute significantly to crop pollination. For example, alfalfa pollination by alfalfa leafcutter bees is worth $7 billion per year in the United States. Other bees can also boost the result of honey bee pollination—in almond orchards, honey bees are more effective when orchard mason bees are present. The more bee species, the merrier the harvest!
While growers often rent honey bee colonies to pollinate their crops, some wild bees pollinate certain crops even better than honey bees do. For instance, bumble bees are more effective pollinators of tomato because they do something honey bees do not: they shake pollen out of flowers with a technique known as buzz pollination. Likewise, native squash bees are better pollinators of cucurbits—unlike honey bees, they start work earlier in the day, and males even sleep in flowers overnight.
How can I help honey bees and other bees?
When it comes to land management and pest management practices, some bees need more accommodations than others. That's why it is important to know what bees are present in your area and important to your crop, and plan for their needs. Use this bee monitoring guide from the University of California to identify the bees present on your farm.
You can help all kinds of bees by using integrated pest management (IPM). This means using nonchemical pest management methods (cultural, mechanical and biological control), monitoring for pests to determine whether a pesticide is needed, and choosing pesticides that are less toxic to bees whenever possible. Check out the UC IPM Bee Precaution Pesticide Ratingsto learn about the risks different pesticides pose to honey bees and other bees, and follow the Best Management Practices To Protect Bees From Pesticides.
Bees also need plenty of food to stay healthy and abundant. Plant flowers that provide nectar and pollen throughout the year. See the planting resources below to find out which plants provide year-round food for specific types of bees.
Like honey bees, native bees need nesting areas to thrive. Bumble bees, squash bees, and other bees nest underground. Ground-nesting bees may require modified tilling practices (such as tilling fields no more than 6 inches deep for squash bees) or no-till management to survive. For aboveground nesters like carpenter bees and mason bees, consider planting hedgerows or placing tunnel-filled wooden blocks around the field. See the habitat resources below for more information about native bee nesting in agricultural areas.
Enjoy your “beesearch!”
Bee Habitat Resources
- Habitat for Bees and Beneficials
- Managing Wild Bees for Crop Pollination
- Native Bee Nest Locations in Agricultural Landscapes
- Farming for Bees: Guidelines for Providing Native Bee Habitat on Farms
- Hedgerow Planting for Pollinators: Central Valley, Central Coast, Southern California
- Conservation Cover for Pollinators: Central Valley, Central Coast, Southern California
- The Integrated Crop Pollination Project: Tools for Growers
- Insect Pollinated Crops, Insect Pollinators and U.S. Agriculture: Trend Analysis of Aggregate Data for the Period 1992–2009.
- Native bees are a rich natural resource in urban California gardens. (PDF)
- Honey bees are more effective at pollinating almonds when other species of bees are present.