Welcoming Back our Familiar Foes

The beautiful thing about being some of the first to have plants in the ground first is, of course, early abundance and garden joy; the downfall is that the pests also love the early growth. These past few weeks a good bit of gardening in community has meant managing pests in community, with bouts of frustration, triumph, and good lessons. This year, following the spotting of our first potato beetles, Vic Izzo, entomologist, professor, gardener, researcher and more, paid us a visit to teach us about the pests in our garden.

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Vic teaching us about pests in the garden

Before we began identifying pests, Vic introduced us to the idea of integrated pest management. Pest management methods fits, more or less, into four categories: cultural, mechanical/physical, biological, and chemical. These represent varying levels of intervention and are traditionally thought of as a hierarchy, with cultural as the least invasive and chemical as the most. Vic encouraged us to think less rigidly about the “hierarchy,” and address our unique circumstances as small scale, community gardeners by mixing and matching pest management methods.

Here are our most familiar and persistent pests, with Vic’s suggestions, as of the end of May:

Flea Beetles: Flea beetles overwinter in the soil and emerge as soon as there’s plant matter to munch on, aka our brassicas. The most common indicator that they’ve found your young brassicas is many tiny holes in the leaves of your plants. For us, this happened very quickly. Our first pest management effort was covering the plants with row cover. Larger brassicas like cabbage, broccoli, kale etc. can survive flea beetle bites once they get bigger, so we were able to use row cover while they were young. This would be considered a physical/mechanical pest control, because we created a physical barrier to keep the beetles out. Something else we’ve done to control flea beetle is spray Neem Oil, an organic, plant based oil, directly onto the plants. Sometimes row cover just isn’t enough, or it doesn’t fit over your beautifully large broccoli, or it’s causing other pests to breed around those plants (swede midge in our case), or it’s keeping beneficial insects (like pollinators and natural predators) out. We’ve taken row cover off for all of those reasons in the past few weeks. Monitoring the plants regularly, such as every time you water, is crucial at this stage to identifying the best pest management method for your unique garden.

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Flea beetles on a cabbage leaf

Leaf Miner: Leaf miner most commonly, and most drastically, affect our spinach, beets, and Swiss chard. They lay white eggs on the back of the leaves and then burrow into them, eating away at the cells, leaving only their paths and the shell of the leaf. Leaf miners leave the leaves when they are adults and then they fly away to continue wreaking havoc. We typically manage, or try to manage, leaf miners by pruning off any leaves with damage (and taking them far, far away from the garden) and mushing eggs off where we see them. However, these are often persistent and very hard to manage even with that. Vic had recently heard from an entomologist colleague that they had had luck using sprays made with Spinosad, a naturally occurring bacteria, in controlling leaf miner. The spray he brought us is called Captain Jack’s Deadbug, but it is also bought in larger quantities at a different concentration under the name Monterey. This could either be considered a biological or chemical control, depending on what you consider the bacteria. Vic told us we didn’t need to panic and use it yet, but to try it out in the case of a true infestation.

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Leaf miner damage on Swiss chard

The list of pests for us goes on, including three striped potato beetle on our Solanaceaes, slugs on our cabbage, and more that we are anticipating with row cover and leaf checks. If you have any unknown pests in the garden or need advice on managing them, feel free to reach out to UVM Extension’s Plant Diagnostic Clinic here. In the meantime, we harvest and enjoy each other’s company in the garden!

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Another garden guest hanging out in the hose

 

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Week 7: the rise of the Colorado Potato Beetle and the resilience of the garden.

It sure seems as if the growth of our potato and tomato plants has been matched by the arrival of the Colorado Potato Beetle. These pests, distinguished by their zebra-striped backs and hearty size (relative to the three-striped beetle that is) have made camp on our potato plants, unafraid to visit the nearby tomatoes.

07-02-16 CTGTT Potato beetles in hand
Two adult Colorado Potato Beetles with a fairly large larvae between. The larvae, hatching from a bright yellow-orange egg, begins its life as a dark red (nearly black) speck. It eats and eats and grows and grows, becoming plumper and lighter in color, eventually developing the markings shown here. Because the larvae must begin feeding as soon as it is born, simply wiping the eggs off of the leaves of the potato (or tomato) prevents the arrival of the next generation. It’s certainly more efficient to target the non-moving eggs!

Contrary to their name, the Colorado Potato Beetle is an invasive species that arrived here from Mexico. In Mexico however, the beetles are not pests because they are controlled by natural predators and distinct environmental conditions. In Vermont, we the gardeners are tasked with the predator role.

Our primary method of control has been careful, daily picking. I quite enjoy the act. It provides the opportunity to tune into each plant, touching its leaves and giving it a good once-over from above and below. I tend to carry a jar of soapy water and gently drop the adults, larvae, and eggs into the jar as they appear on the plants. Picking beetles is time consuming and, despite our best efforts, has not noticeably reduced the population. In fact, it appears to be growing – which makes sense as each cluster of eggs represents the beginnings of 10-30 beetles.

We’ve decided to introduce a foliar spray, hoping to get ahead of the problem and protect the potatoes growing below. We’ve begun an experiment of sorts – spraying a homemade garlic-chili repellent on one-half of the crops (recipe below), and using a store-bought Neem Oil on the other half. Results to follow…

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Neem Oil is an insecticide that can control the Colorado Potato Beetle in its egg and larvae stages, while also providing healthy enzymes to the plant. Said to be most effective on young plant growth, neem is used to manage over 200 species of chewing + sucking insects.

As I said, pests are matched by growth and growth allows for bountiful, colorful harvest:

06-30-16 CTGEA Gems of the earth - radish up close
The vital red of the radish
06-30-16 CTGEA Chrissy holds the bundle of greens
Spectrum of ‘greens’ from purple to red to blue
06-29-16 CTGTT Amy in a rainbow of cut flowers
Not to mention the oranges, yellows, bright whites, and pinks!

And the recipe for the garlic-chili spray:

·         5 garlic cloves

·         2 Tbsp hot pepper flakes

·         3 cups water

·         ½  small onion

·         1 tsp liquid soap

Put all the ingredients (except for the liquid soap) in a blender. Blend well until the solids are broken down. Transfer to a container and mix in 1 tsp of dish soap. Let it sit in the refrigerator overnight. Strain through a sieve and discard the solid bits. Use a spray bottle to evenly distribute the liquid over the foliage in order to deter the beetles from laying eggs.

Week Four: Acquainting ourselves with the solanaceae family, and with the three-striped potato beetle

Cool weather and a good heavy rain offered sweet relief to our brassicas and good conditions for transplanting starts from the solanaceae family. Solanaceae, also called nightshades, are characterized by their flowering plants and include the many varieties of potatoes, tomatoes, tomatillos, eggplants, and peppers.

6-1-16 CTGTT Solanaceae plants await student arrival

The transplant was quite similar to the transplanting of the brassica family. Tomatoes require slightly more attention as they tends to grow into heavily fruit-bearing and therefore top-heavy plants. Our tomato transplants ranged from about six to twelve inches and had a soft, white fuzz quality to the bottom half of the stalk. This fuzz is the beginning of what will become a strong root system, and therefore wants to be submerged fully underground. Tomatoes want to be planted in a hole that is one-half as deep as their overall height (at the time of transplant). This requires the careful removal of low-growing branches. Finally, removing all flowers and suckers will encourage the plant to allocated its energy to the establishment of a strong and developed root system. This is crucial to the health of the plant.

Here is Carolina offering guidance on tomato planting:

6-1-16 CTGTT Carolina offers guidance on planting tomatoes

Visit the Hudson Seed Library for more on transplanting and tending tomato plants.

 

Eggplant and peppers need not be buried as deep as the tomato. Just slightly above the existing soil line is fine. Pinching off any premature flowering will improve the health of the plant. Below is Alex choosing what to plant from a variety of peppers!

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As for the tomatillo, the transplant is just like that of the eggplant and the pepper. The plant itself though will grow to be quite large and so we’ve dedicated one of our communal beds to the tomatillo crop. To no surprise, the three-striped potato beetle arrived within two weeks of planting.

 

Also called the three-lined potato beetle, this pest can live off of the leaves of any member of the solanaceae family but has a preference for the tomatillo. We had the opportunity to observe about twenty beetles spread across our five tomatillo plants. It was mid-morning, they were mating, and the backsides of the plant’s leaves were marked with the yellow-orange eggs of the next generation. These pests cannot merely be pulled off of the plant. They must be removed from the garden – either in a tightly sealed container or in a cup of soapy water. The eggs need only to be wiped off of the leaves for the newborns require immediate sustenance and will not survive if born away from their food source.
Read on for a more thorough look at the three-striped potato beetle.