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Table of Contents:
This Month's To-Do List | Now Is the Time | Friends of Urban Agriculture
Beating the Bugs | Organic Vegetable Garden
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June To-Do List
- Continue to harvest for the best taste and ripeness and to encourage new growth.
- As temperatures rise and spring rains become less frequent, you may need to water your vegetable garden more frequently and replace mulch to help retain soil moisture.
- Weed your garden regularly and inspect plants for disease or insect damage.
- Use a light row cover for pest protection.
- Place straw under the developing fruit of melon, pumpkin and squash.
- Harvest strawberries, blackberries and raspberries daily.
- Direct sow summer crops for continuous harvest: beans, okra, squash, cucumber, pumpkin, melon, sunflower, most herbs, and some other crop varieties (follow instructions on the seed packet).
- Provide stakes, trellises or cages for tall plants to prevent damage.
- Plant more basil (as often as every 2 to 3 weeks) and other heat-loving herbs such as rosemary.
- Continually deadhead plants and herbs to discourage bolting and promote new growth.
- Prune tomato plants and other crops to remove debris and open up plants to more sun.
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- Harvest garlic late June to early July when tops are half green to half brown.
- Start Brussels sprouts indoors for fall planting.
- Continue to monitor sweet potato slips until sprouts grow 5 to 6 inches. Then pluck them, and plant slips in the garden in mid to late June.
 Plant, Pest, or Other Garden Questions?
Contact the Extension Master Gardener Help Desk. Even during the pandemic, knowledgeable Virginia Cooperative Extension volunteers are available to answer questions!
MGNV June 2021 Events and Classes
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Now is the time to harvest and monitor for healthy growth
Plant sweet potato slips in mid to late June in wide rows, with 8 inches between each slip and soil mounded up to a depth of 4 inches. Weed and water regularly. More growing information is available from Clemson Extension.
As you continue to harvest your spring vegetable crops and these crops become spent, pull out the whole plant (debris and roots) to give more room for your summer vegetables to grow. If you have some extra garden space, consider succession planting, or planting another row of beans, peppers or tomatoes. This will provide you a second or third harvest of produce later in the summer. Read more about succession planting and other intensive gardening methods from the University of Maryland Extension and VCE. See also last month's post on inter-cropping techniques. Check area planting guides for recommendations on when to plant and harvest certain plants during warmer summer months.
Keep an eye out for emerging insects and rodent pests. Certain plants are especially vulnerable to insect pests, such as squash, cucumbers, tomatoes and eggplant. Gardeners need also to be on the lookout for color changes and/or damage on leaves and stems that could be indicators of plant disease and other environmental conditions. Signs of fungal disease on plants (especially cucurbits) is also important to detect early. Quickly remove affected plant parts or the entire plant to avoid spreading the disease to other crops. Note that plant problems may occur for a variety of other reasons, such as too much or too little water, lack of sufficient sunlight, unhealthy soil, or drastic temperature changes. To increase success, continue to follow recommended best practices by rotating your crops, watering correctly, cleaning out plant debris and weeds, choosing plants/seeds of disease-resistant varieties, and planting companion plants. These types of best practices are ways to improve your garden’s health and make it more resistant to plant disease and insects. The practices are part of integrated pest management (IPM), a gardening practice based on using mechanical, biological, and cultural methods of pest control. For more information, see the 2021 Pest Management Guide from VCE.
See Beating the Bugs for more information
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These recorded VCE/MGNV classes will be of special interest:
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We invite you to join us at the Annual Green Home and Garden Tour taking place virtually on June 4, 2021, from 12:00 to 1:30 p.m. This tour will feature homes with energy-efficient technologies, solar panels, and green renovations; watershed-friendly gardens, native plants, rain gardens, rain barrels, and edible landscaping.
This year, the tour will feature short videos of homes and gardens together with an online meet-the-host event where you can ask the hosts your questions directly in small breakout rooms. We will also have breakout rooms featuring local experts on topics including gardening, stormwater management, and green home renovations. FOUA’s Project HUG is a featured garden.
Join us to get ideas and inspiration for your own home and garden! The suggested donation is $5 per household.
This event is sponsored by Arlington County’s Office of Sustainability and Environmental Management, EcoAction Arlington and Virginia Cooperative Extension.
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Illustration © Melissa Joskow
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Pests of Tomatoes, and Peppers
Ah, the joys of harvesting fresh peppers and tomatoes that you have grown yourself! It’s June and your warm season crops should be coming into their own. In particular the members of the Solanaceae family — the peppers, tomatoes, and eggplants — are just loving the heat. A few insect pests love them as much as we do. By far the most serious of these are the flea beetles. These tiny, quick moving, dark blue, black, brown, or striped beetles feed on eggplants, pepper, cole crops, beets, spinach, mustard, and radishes. Also significant in Virginia are the Colorado potato beetle, whitefly, and grasshopper.
| Flea Beetles
Eggplant flea beetles (Epitrix fuscula)
and damage to eggplant foliage
(Source: David Cappaert, Bugwood.org)
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Flea beetles emerge from the soil in early spring to chew holes in the leaves, mate, and lay eggs near the soil line. Its larvae feed on roots and pupate into adults in 2-3 weeks. There are multiple generations per year.
Control these with crop rotation, fall tilling of debris into the soil, and using a row cover of floating fabric. Once infested, use diatomaceous earth or pyrethrin sprays for heavy infestations. Azadirachtin or kaolin clay provide good control. Always avoid applying insecticides to flowering plants and always read the label. |
Whiteflies
Whiteflies, in addition to being tomato pests, are also a serious kale and collards pest. Related to scale, leaf hopper, and mealybug insects, adults are only 2 mm long and resemble small white moths. Whiteflies can vector virus diseases, and populations can build up to large numbers very quickly, which will kill plants. Immature pupal cases look like pale yellow-white scale insects on the bottom of leaves.
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Whiteflies with yellow larvae and silvery pupal cases (Source: M.J. Raupp, University of Maryland) |
When buying plants inspect carefully to ensure that they are pest free. Interplanting susceptible crops with small flowering plants will provide some biological control. Control the egg and immature stages with oil (horticultural, canola, neem) sprays or with insecticidal soap. Completely saturate the underside of all leaves and repeat application in 2 weeks. Heavier infestations may require use of imidacloprid, permethrin, or pyrethrins. Be mindful of the days before harvest (pre-harvest interval) listed for every chemical control. These range from 1 to 21 days.
Peppers 🫑
Although peppers both hot and sweet are remarkably easy to grow, our Virginia Tech specialists say that in addition to Grasshoppers and the European Corn Borer, the most common pests are aphids, thrips, and stinkbugs.
Aphids: See April Between the Rows newsletter.
Thrips
Thrips are tiny and hard to see. The winged adult, only 1/25 inch long, is bright yellow, and the even smaller immature thrip is wingless. They do deep damage to the leaf or flower buds, which is not evident until the buds open revealing distorted, withered, and/or brown or white dead plant tissue.
Thrips lay eggs in early summer on buds and leaves. Multiple overlapping generations of thrips can occur in Virginia on onion, bean, carrot, cabbage, cauliflower, celery, cucumber, melon, pea, squash, tomato, and turnip.
Control options are chemical control, dusting with diatomaceous earth, some predation by minute pirate bugs and lady beetles, and organic controls such as spinosad, insecticidal soap, and pyrethrins.
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Damage to sweet pepper from an infestation of thrips
(Source: Vivek Kumar, Entomology and Nematology Department, University of Florida)
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Female (left) and male chili thrips
(Source: University of Florida)
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Tomatoes 🍅
Tomatoes are the source of our most frequently asked vegetable insect control questions. In addition to flea beetle, aphids, thrips, and whitefly that we covered earlier, we also need to fight off tomato’s most common pests — stink bugs, hornworms, spider mites — as well as blister beetles, tomato russet mites, cabbage looper, Colorado potato beetle, cutworms, grasshoppers, leaffooted bugs, and fruitworms/corn earworm.
Stink bugs
 Adult brown marmorated stink bug
(Source: Courtesy of David R. Lance, USDA APHIS PPQ, Bugwood.org) |
Stink Bugs are about 5/8 inch long and are shield shaped. Their eggs are barrel shaped and laid 20-70 in clusters on the bottom of leaves. Two of the most common here are the harlequin bug and the brown marmorated but green stink bugs and leaffooted bugs cause similar damage and are controlled in the same manner.
Adults and nymphs feed on plant buds and seedpods, which results in malformed buds and fruit. On okra and bean pods, the damage appears as raised spots. On tomatoes and peppers, white marks, often resembling halos, appear on the fruit. |
See a gallery of stink bug damage here: https://www.stopbmsb.org/where-is-bmsb/bmsb-damage-gallery/
Cultural control of some stink bugs can be achieved by removing weeds and wild fruit trees around gardens, and organic controls are limited to pyrethrins. Various chemical insecticides are effective only as contact sprays and provide very little residual control. Systemic insecticides are licensed for use on food crops, too, but are rendered nearly useless by their 21 day pre-harvest interval requirement
Spider mites
These tiny, about 1/50 of an inch, arachnids are pale in color, often with two dark spots. They are indiscriminate feeders on beans, tomatoes, and many bedding plants. Mite feeding causes the leaves to look sandblasted with lots of tiny yellow or off-white spots. Spider mites leave webbing and debris on leaves and plant stems. Heavy feeding can cause an entire leaf to yellow and eventually turn brown.
Chemical controls are not recommended because they make the spider mite problem worse by killing off beneficial mites and predators. Make sure plants are well watered and remove and compost any green weeds and clumps of grass in the winter. Predatory beneficial phytoseiid mites are available for purchase. |
Spider mite damage on tomato
(Source: Peter L. Warren, Arizona Daily Star) |
Hornworms
Defoliation on tomato plant caused by a single tomato hornworm (Source: Utah Vegetable Production & Pest Management Guide)
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Two species of hornworm damage tomato plants in Virginia: the tobacco hornworm and the tomato hornworm. Both of these are large (up to 4”) and are green with diagonal lines on their sides and a horn on their rear ends. Hornworms feed on leaves and fruit and are almost always on the upper top part of the plant.
Controls include handpicking the worms and destroying any that don’t have wasp cocoons on them because these will provide biological control on future generations. Organic control is provided by Bacillus thuringiensis when hornworms are less than 1/2 inch long. Chemical control with capsaicin and oil of mustard, Beauveria bassiana, neem oil, azadirachtin, and pyrethrins must also be done when the larvae are less than 1/2 inch long. |
Next Month: Pests of Cabbage, Kale, and Collards
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May Observations from the Organic Vegetable Garden
All photos by Nancy Dowling 2021
This year at the MGNV’s demonstration Organic Vegetable Garden (OVG), Cherry Belle radishes have outperformed our other favorite, French Breakfast. Some of the French Breakfasts became woody.
The rain has not kept us from harvesting kale, lettuce, and other cool-weather crops that we overwintered, but we have begun pulling some of these crops as they begin to bolt. Vegetable gardening constantly reminds us of nature’s cycles!
Kathie Clements harvesting kale in the rain. |
Also harvesting now: Overwintered spinach.
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We have started planting the warm weather crops, although the variable weather and fluctuating temperatures have made it difficult to know when it is safe to plant crops such as tomatoes. We usually try to wait until nighttime temperatures are consistently over 50 degrees, but this year we planted some of the cherry tomatoes while we were still in the prolonged cool spell. We’ll report on how they do.
Kristi Provasnik planting bush beans
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We are also doing more succession planting and interplanting. Succession planting involves planting crops (such as beans) every 2 to 3 weeks to extend the season over several weeks. We are interplanting flowers and herbs as we pull the kale and other cool-weather greens in order to plant greens that can take our hot summers. We hope that the flowers and herbs will attract beneficial insects or confuse the usual pests. There is a newly published book, Plant Partners: Science-Based Companion Planting Strategies for the Vegetable Garden, that explores the benefits of interplanting. |
The OVG is participating in a Cornell University study to track downy mildew on cucurbits. We will also report on downy mildew on basil, particularly the Genovese type, which has been a problem for us later in the season.
Most overheard comment from visitors to the OVG: I didn’t know that asparagus plants look like that!
Stop by and visit the Organic Vegetable Garden at Potomac Overlook Park
2845 North Marcey Road, Arlington, VA 22207
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For more information on Vegetable Gardening, check out Select On-Line References for Kitchen Gardening on the Master Gardener of Northern Virginia (MGNV) site. MGNV volunteers support the work of Virginia Cooperative Extension's public education outreach.
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