Questions from the Master Gardener Hot Line: Nematodes to the Rescue!

Nature's Way to Control Beetles and Grubs

by Pat Vance

Volunteers for the Philadelphia Master Gardener Hot Line have researched and answered some interesting questions. From time to time, we'd like to share some of those with you.

Photo: Philadelphia Master Gardeners

If you have a question about gardening, call us at 215 314 8711 or send an email to philadelphiamg@psu.edu

Photo: PSU Extension

Beetle and Grub Infestation:

His pepper plants did great for several years, but during the last three years, they have suffered from beetle infestation. He begins to see grubs, the larval stage, starting in June. By the end of the month, the beetles are swarming. They devour blossoms and chew through the petioles of the leaves, leaving behind a ragged sorry-looking stem with dead leaves scattered on the ground. When the beetles disappear in another month, the plants recover. But his crop of peppers is diminishing with each season. He doesn't want to use pesticides. Is there another option?

Photo: PSU Extension

Cultural Practices: 

He can till the soil in the spring to remove the grubs, and he can rotate plant positions every year.  

Turning over the soil has advantages in a few ways, but it can also increase annual weed growth. It is also tedious and may not be completely successful for removing all the grubs.

Photo: OR State Univ Extension Master Gardener

Rotation of crops is always a good idea for many reasons. In this case, the beetles don't bother the tomatoes or leafy greens. They go straight for the peppers.

In a large garden, moving the peppers from year to year can help. However, this man has a small garden. Flying beetles won't have any trouble locating plants that are now only a few feet from last year's site.

Biological Control: 

Photo: PSU Extension

Nematodes to the rescue! Nematodes are tiny, clear worms that occur naturally in nearly every ecological niche on earth. There are thousands of kinds of nematodes found in soil, and fresh or salt water from the hottest to the coldest climates, including mountains, deserts, and deep ocean trenches. Most of them are tubular, tapered at each end, and cannot be seen with the naked eye.

 There are a few nematodes that can cause damage to plants, but the ones of particular interest to gardeners are parasitic nematodes, often simply called beneficial nematodes.

Photo: PSU Extension

Beneficial nematodes kill the larvae of many species by piercing and entering them, and then secreting toxic bacteria.

Photo: PSU Extension

The nematode divides inside the dead grub. Then the progeny move on through the soil, using differences in heat and CO2 to find more grubs. Many kinds of soil-dwelling pests can be controlled this way, including beetles such as Japanese and Green June beetles, maggots, fleas, and several kinds of weevils and borers. They are useful for infestations of grubs on lawns as well as in garden beds.

Here is a link to an article on beneficial nematodes from Penn State Extension

http://ento.psu.edu/extension/factsheets/parasitic-nematodes

Photo: Arbico

The nematodes should be applied when the grubs are growing in the soil. For many insects, that's in the spring, but be sure to identify your garden pest carefully and understand the timing of its life cycle.

A few million nematodes can be applied to a 1000 square-foot garden and successfully contain pest infestations. One application may be enough, but in some cases, the nematodes must be re-applied for a couple of years.

You can buy beneficial nematodes from a few sources. Here are links to a few:

Gardens Alive!: https://www.gardensalive.com/article1101

Buglogical: https://www.buglogical.com/beneficial-nematodes/

Arbico Organics: https://www.arbico-organics.com/category/beneficial-nematodes

Arbico has a very good FAQ page on beneficial nematodes:

https://www.arbico-organics.com/category/beneficial-nematodes-faqs

Application:

The nematodes may arrive suspended in a liquid or gel, on a sponge, or in moist granules. They are added to water, gently stirred to break apart any clumps, and allowed to soak for a short time. The exact procedure will be explained in the product insert.

Photo: City of Tillamook, OR

The slurry is then sprinkled on the garden. This can be done with anything from a watering can to commercial sprayers. They will settle to the bottom of the can or bucket, so the water should be stirred frequently during the application. They will clog fine filters and meshes, so it's best to leave those off. Remember that nematodes are living organisms and should be handled gently.

Nematodes need moisture, so the soil should be watered well before application and then lightly afterward. Late afternoon is ideal to avoid the hottest temperatures of the day until the nematodes have established themselves in the ground.

For more information, here are a couple of additional links:

UMass Amherst: https://ag.umass.edu/landscape/fact-sheets/beneficial-nematodes

UMD extension: https://extension.umd.edu/hgic/nematodes

Using parasitic nematodes is a safe, sustainable, and easy way to manage garden pests that live in the soil.

Photo: PSU Extension

If you have any other questions and are not sure where to turn, ask the Hot Line! If we don't know the answer, we know someone who does!

Winter Pruning Tips

Laddy Lau

In early February, a dedicated group of Master Gardeners took part in a fruit tree pruning effort at the Permaculture demo garden in Fairmount Park.

Pruning your fruit trees can be captured by the 3 Cs:

• crossing
• competing
• crowding

The three Cs help to provide light, space and allow for continued growth. The group helped to prune pear and pie cherry trees in addition to brambles, like blackberries and raspberries.

When you consider pruning, there is a lesser chance of disease in the winter compared to the growing season.  Despite the temperature, it is always a good idea to sterilize your tools with alcohol before and after pruning.

       


For trees over 10 feet, you may choose several options to prune whether it is with a loppers, pole saw and/or pole pruner (images below from left to right).  


Whichever tool you use, the basic concepts apply:

• Cut off root suckers and sprouts 
• Remove a competing, co-dominant leader
• Eliminate branches that rub together and block light

• Thin excessive branches to reduce competition for light, water, and nutrients
• Remove a few of the lowest limbs but others are temporarily left to help the trunk develop more taper and strength
• Remove narrow angled branches

For your brambles, here are a few tips:

• Raspberries

1. Prune grayish, peeling bark canes that bore fruit last year; they won't fruit again
2. Cut back spindly or short canes
3. Thin raspberry canes so that 4 to 5 canes/foot in a row are the healthiest, tallest, and thickest
4. Tie your sturdy canes to your fencing

Blackberries

1. After harvest, prune canes that bore fruit last year; they won't fruit again
2. Prune growing tips to enhance next season's growth
3. Cut back spindly or short canes
4. Thin blackberry canes to 5 to 7 canes/plant 

Pruning of second year bramble canes 

For more detailed information, see these additional links.

• https://extension.psu.edu/pruning-basics
• https://extension.psu.edu/pruning-landscape-trees
• https://www.arborday.org/trees/tips/keys-to-pruning.cfm

Milkweed: More than just a food for the monarch butterfly

Lisa Kucinskas

            In doing research on milkweed for my Master Gardener training presentation, I learned quite a few interesting facts about these plants beyond their best-known role as food for the larvae of the monarch butterfly.

Milkweed comes from the genus Asclepias, consisting of 130 species, of which all are herbaceous perennials. They are found in the Americas, with most living from Mexico on northward to Canada. There are 11 varieties that are native or naturalized in Pennsylvania. Milkweed is not self-pollinating; it needs another milkweed plant to pollinate with it. Common milkweed (Asclepias syriaca), the variety that serves as host for the larval stage of the monarch butterfly, is clonal and can be considered aggressive. Butterfly weed (Asclepias tuberosa) is the milkweed plant most commonly found for sale at garden centers and in our gardens. 

Common milkweed (Asclepias syriaca); Photo credit: David Taylor, https://www.fs.fed.us/wildflowers/plant-of-the-week/asclepias_syriaca.shtml

Milkweed contains cardenolides, a steroid that acts as an emetic (a substance that causes vomiting). This is why the plant is considered toxic. Symptoms of cardenolide toxicity are depression, dizziness, labored breathing, and seizures. However, there are beneficial modern medical uses for milkweed as well, such as to treat heart failure, to relieve inflammation of the lung, and as a promising new anti-cancer drug.        

There are many other diverse uses for milkweed. The oil from the seeds is used as an industrial lubricant; Thomas Edison developed rubber from milkweed latex; and the fiber from milkweed seed pods is used as stuffing for pillows and comforters. During World War II, school children across America gathered 25,000,000 pounds of seed pods for the United States Navy to fill life vests with the seed fibers (called coma), since the kapok from Asia was no longer available. The plant fibers have been used for hundreds of years by the Native Americans for rope, string and cloth, and presently farmers in Vermont are growing milkweed for Canadian clothing companies.

Butterfly weed (Asclepias tuberosa); Photo credit: www.missouribotanicalgarden.org

Milkweed nectar was used by the early French Canadians as a sweetener. Euell Gibbons wrote in his book Stalking the Wild Asparagus of the many other food uses for the plant: New shoots up to 6" can be served like asparagus and newly opened top leaves like spinach; unopened flower buds are similar to broccoli, and the young pods cook like okra. Though milkweed is extremely bitter, boiling the water and changing it several times during the cooking process will take care of this. To quote Gibbons, milkweed is a "very acceptable vegetable if properly cooked.”

For more on milkweed, see another recent Master Gardener post here.

SOURCES:

Anurag Agrawal, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution

Euell Gibbons, Stalking the Wild Asparagus

Mary Joy Haywood, Phyllis Testal Monk, and Members of the Botanical Society of Western Pennsylvania, Wildflowers of Pennsylvania

Jennifer Levitz, “This Winter's Hot Fashion: Parkas Stuffed With Vermont Weeds,” The Wall Street Journal (September 28, 2017)                                                                                                                                                                                                                                                                                             

Time to plan this year’s garden

by Michelle L. Dauberman

The time for planning this year’s garden is upon you yet during these cold days you may be finding it hard to get back into the swing of things so here’s an inspired plant list to get you started!  Happy Gardening!

Arugula, 'Roquette' (Eruca vesicaria subsp sativa)

Beans, 'Maxibel' (Phaseolus vulgaris ‘Maxibel’)

Beans, 'Serengeti' (Phaseolus vulgaris ‘Serengeti’)

Beans, ‘Black Turtle’ (Phaseolus vulgaris 'Black Turtle’)

Beans, 'Soleil' (Phaseolus vulgaris 'Soleil Filet')

Beets, 'Golden Orange' (Beta vulgaris 'Golden')

Cardoon (Cynara cardunculus)

Cucumber, 'Mouse Melons' (Melothria scabra) 

Endive, 'Tres FIne' (Cichorium endiva ‘Tres Fine’)

Kale, 'Dwarf Blue Curled Scotch' (Brassica oleracea 'Dwarf Blue Curled Scotch')

Lettuce, 'Kweik' (Lactuca sativa)

Lima Bean, 'Big Mama' (Phaseolus lunatus)

Okra, 'Burgundy' (Abelmoschus esculentus)

Spinach, red stemmed Malabar (Basella alba 'Rubra')

Tomatoes, 'Black Cherry' (Lycopersicon lycopersicum ‘Black Cherry’)

Tomatoes, 'Black Vernissage' (Solanum lycopersicum 'Black Vernissage')

Tomatoes, 'Amish Paste' (Solanum lycopersicum ‘Amish Paste’)

Tomatoes, 'Sungold Select 11' (Solanum lycopersicum ‘Sungold Select’)

Basil, 'Holy' (Ocimum tenuiflorum)

Basil, 'Napoletano' (Ocimum basilicum ‘Napoletano’)

Rosemary, 'Barbecue' (Rosmarinus officinalis 'Barbeque')

Tarragon, 'Siberian' (Artemisia dracunculoides)

Looking for more inspiration?

Come join our Master Gardeners across the state to get ready for the new growing season at the “Master Gardener Spring Gardening Seminar.”  https://extension.psu.edu/spring-gardening-seminar?

Where trade names appear, no discrimination is intended and no endorsement by Penn State Extension is implied.