Know Thine Enemy


Caution: the topic is important and this article is a bit long. So get yourself a drink of choice, settle into something comfortable and read.

As gardeners, we are in an age old battle with pests, marauders and acts of nature. Traps, sprays, baits, decoys and such have occupied the attention of every generation. Growers try to come up with hardier, disease resistant plants all the time. Inventors and scientists attempt to answer the besieged gardener’s prayers with new contraptions and devices while yet more scientists introduce new strains of bugs, genetically modified plants and compounds to do battle. Its always a case of trying to stay one step ahead of the enemy isn’t it?

Just as we treat our own ailments specifically, it behooves us to do the same with our gardens and crops. To truly understand the problem translates to going beyond addressing just the symptoms and targeting the causal agents themselves. General plant hygiene is a necessity. Regularly cleaned equipment and tools, uncontaminated compost, mulch, water and soil, proper air circulation are all part of good plant husbandry. Yet, despite our best efforts, disease and pests will appear. So its important to study up.

While it is beyond the scope of this site to enumerate all the problems and solutions, I want to emphasize that it is incumbent on each of us to take responsibility to learn about such matters and take the appropriate action. To that end, I’d like to summarize a talk I attended recently. Titled “Bees, Trees, and Berries: How global plant movement and change can affect our gardens” it was given by Dr. Margery Daughtery. Informative and interesting, Margery managed to convey a serious, heavy topic with humor and clarity.

To start with, the particularly hard and wild winter is some indication of the climate changes underway. It is up to us to adapt and cope. There has been the thought that the harsh winter might have helped in diminishing the presence of ‘stink bugs’ and other pests. Margery broke the news gently – not true. The pests will be slow to start but being rather well suited to the human lifestyle, they are fully capable of getting through rough times. Be warned and stay vigilant.

Microbes have the happy (for them) ability to mutate. So, as we introduce resistant plants and treatments, we can expect to see many of the pests mutate accordingly. This has been already observed in fungi that cause rust diseases. Meanwhile, something remarkable and alarming has been observed in Europe. The TRSV virus is a well recognized plant pathogen. Its genetic material is RNA. This has mutated and converted to get into the central nervous system of the honeybee. It is now thought of as a significant cause of colony collapse disorder in the European Apis mellifera. Scary right?

Regarding boxwood blight – first and foremost one must be certain the problem is indeed blight and not stress which can be due to the normal effects of winter or the heat of summer. There is a fungicide spray available to prevent the blight. Margery pointed out that it did not make ecological or economic sense to spray year round. Since spikes in the blight have been noted in certain months, it would be prudent to spray just before those periods. What is yet to be determined is exactly when would be those ideal times. Research has been slow. Stay tuned. On the up side, this disease is not wind borne and is slow to spread. Certain types of Korean boxwood appear to be more resistant. Many alternatives to boxwood exist. Let me know if any of you need more information.

Speaking of slow research, there is still no good news with the problem of powdery mildew in impatiens. For now, impatiens lovers are still advised to plant New Guinea impatiens.

The situation with the rose rosette nuisance, if a plant is affected, pull out the whole plant and dispose off with the garbage. Do not compost. Knock Out roses are observed to be more susceptible. Select hardier roses by looking up (Google) university sources whose research is the most reliable. Help steer Extension Centers like Cornell and botanical gardens by seeking and supporting their work. They really are our command central for all matters horticultural.

Planting native trees is one of the single most positive action we can take. Bringing balance to the ecology, maintaining equilibrium of the carbon-cycle and fostering the helpful fauna, forests cannot be beat. As I’ve said here many times, go forth and plant a native tree. Arbor is this Friday – observe it!

This talk was the third and final part of a series. The crux of it is that we must be vigilant about alien diseases and bugs that sneak in not only with plant material from other parts of the world but also hitch rides on palettes and crates for other imports. In my opinion, it is simple enough to say “Grow, make, buy, use American!” but much harder to implement. The world has shrunk and all countries are dependent on each other for so very much. Travel, commerce, tourism has grown. There is no turning back.But we can each do our part I should think?

In the garden, going native is much easier. These plants are naturally hardier, less fussy and more disease resistant. Plant non-invasive, well understood non-natives only. Obtain plants from reputable nurseries and growers – preferably local establishments. Keep in mind, the local places operate under the same conditions as you do. It stands to reason that their plants will do well in your garden.

It ultimately comes down to every gardener to familiarize him/herself with the problems, understand the causes and then act with intelligence and foresight. Know thine enemy indeed.

After such a serious piece, here are some cheery photos. This is why we garden! And remember – my garden is open May 10. Click on the Happenings page for details.
Osteospermum and pansies in urn
Primroses
Red tulips
Fringe tulips. Crystal Palace.
(c) 2014 Shobha Vanchiswar

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3 thoughts on “Know Thine Enemy

  1. Wow. Sobering indeed. On a minor note, can’t believe knock out roses particularly susceptible to rose rosette. Thought they were slightly uninteresting warhorses. Will go native whenever possible. Thanks for uplifting photos. Off to get that drink you recommended.

  2. Thanks for the great info. My biggest problem is that the slugs eat my hostas. Other then beer, what do you recommend?

    • Christina, have you tried spreading crushed shells of mollusks, gravel or gritty sand around your hostas? The sharp edges of these cut into the slugs and hence deter them. Give it a try and let me know?

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