Harlequins Gardens

Boulder's specialist in well-adapted plants

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Home | Blog | Pest Management

Pest Management

Fungus Gnats

Fungus Gnat. Credit CSU Extension Service

Houseplants, especially ones that we keep outdoors in the warm season and bring back inside when frosts threaten, are likely to harbor Fungus Gnats. These tiny black flying insects (about the size of a fruit fly) can be very annoying but are mostly harmless. Adults lay 75 to 200 eggs that hatch in a week in the top 1” of soil, and when the larvae hatch, they survive mostly on soil fungi, but also feed on tender root hairs.  This life cycle lasts about five weeks, although the adults only live about five days. One plant infested with fungus gnats will easily and rapidly spread the insects to nearby plants. [Read More]

The Ups & Downs of July

First, let’s count our blessings: the cool and wet spring has been great for plant growth (and of course, weeds galore!). The profusion of wildflowers this spring has been glorious, the foothills are still green going into July, and conditions for gardening are now quite pleasant. And we will have fruit on most of our fruit trees! Don’t forget to thin them to keep branches and trunks from breaking.

Colorado is well known for surprising weather events, but this year has been exceptional and, in some cases, record-breaking.   [Read More]

MANAGING WEEDS WITHOUT POISONS by Mikl Brawner

Some people repeat Ralph W. Emerson, saying “A weed is a plant whose virtues remain undiscovered.” But although I appreciate that many weeds do have virtues, I doubt that many gardeners would accept that definition as the final word. Most of us have had extensive experience with Bindweed, Thistle, Goathead, Ragweed, Dandelion and Cheat Grass; not to mention some aggressive natives like Whiplash Daisy, Wood’s Rose and Hairy Goldenaster; and certain herbs like mints, Comfrey and Sweet Grass. So in talking about managing weeds non-toxically, the main point seems to be: How can we keep certain plants under control?[Read More]

Hippety Hop …. Right into your garden!

Have you found that rabbits are becoming more rampant?

Due to habitat reduction and fewer predators, many people are seeing more rabbits in their garden. Here are tactics that can help you. 

  1. Strategically place deterrent plants among your more delectable plants. These include: very aromatic plants; prickly and spiny plants; tough, leathery leaves; toxic plants; and milky sap plants. (Ask to see our rabbit-resistant and deterrent list at the Nursery.)
  2. Newly transplanted plants are especially vulnerable and need extra structural protections or odor repellents (below).
  3. Cultural controls include removing protective cover such as brush piles where rabbits may hide. Remember, open space often makes animals more vulnerable to predators.
  4. Chicken wire fencing can be fairly effective if buried 4-8″ under the soil and at least 2′ high – although Eve reports rabbits jumping over 3′ high wire!
  5. Many odor repellents can be helpful, including our non-toxic Plantskyyd (in liquid and pellet forms), and Bobbex liquid concentrate or ready-to-use spray.  Although non-toxic, you may not want to use these products on edibles.  Also, remember to reapply according to directions taking into account current precipitation and irrigation rates.

Insectary Plants: Let Nature Manage the Pests

It’s a common idea that Nature, left to its own devices, comes to some kind of balance. If one organism gets too numerous, something else will increase to reduce that population. In the case of monocultures created by humans, there is an enforced imbalance that has to be propped up with lots of energy and effort. So in the pursuit of sustainability, humans are opening our eyes to the possibility of biomimicry, imitating Nature. We are coming to the realization that biodiversity is far healthier and less energy intensive than monocultures born out of the aggressive hubris to control Nature. “Let Nature take her course.” But we can stack the deck in human favor first.[Read More]

Non-Toxic Weed and Pest Control

Non-toxic Herbicides

Summer is a successful time to kill weeds, either by mechanical weeding or with herbicides. But toxic herbicides, like Roundup are not solutions we recommend. Roundup in particular was once believed to be quite safe, but now is shown to be harmful to soil life including nitrogen-fixing bacteria, amphibians and is a probable human carcinogen. Roundup formulations can be up to 400 times more toxic than the active ingredient, glyphosate.

At Harlequin’s Gardens, we only sell non-toxic products, but not all non-toxic products are actually effective. Four years ago we tested five non-toxic herbicides and found only two to be really effective: 20% Vinegar and Avenger.

20% Vinegar is 20% acetic acid. It is a non-selective organic acid that quickly kills many weeds, then quickly biodegrades. Repeated use can acidify the soil which is usually a benefit in our alkaline soil. Be careful not to spray desirable plants, and be careful to protect your eyes, especially on windy days. It is most effective on small plants. Repeated applications may be necessary on perennial weeds.

Avenger is a citrus oil weed killer that we found to be equally effective as the vinegar. It is certified organic and is biodegradable. Avenger is non-selective so care must be taken to keep spray off desirable plants. It comes in a ready-to-use (RTU) formula and in a concentrate which may be mixed stronger for tougher, perennial weeds. Like vinegar, it is most effective on small plants, and is best sprayed during hot weather in direct sunlight.

In order to “control” bindweed and other weeds with extensive root systems, don’t let new growth get longer than 2″ or the weed will revive.

 

BLISTER BEETLE: We have been hearing reports of Blister Beetle attacking clematis. This is a light grey, long beetle that can defoliate a clematis vine in 2 or 3 days. We have found that an organic product called Veggie Pharm actually kills this beetle. It must be sprayed directly on the beetle. (Don’t try to pick up a Blister Beetle; they can raise a blister)

 

Tree Wrap: We recently saw a big buck with his antlers in the velvet stage. This the time of year deer cause the most damage, when bucks rub their itchy antlers on smooth, usually young tree trunk, tearing the bark. Sometimes a young tree can be girdled in one night. We carry a very good spiral plastic tree wrap that protects trees from deer, rabbits, sun scald in winter. It is superior to paper wraps because it lets air circulate so moisture does not decay the bark. It can be left on in the summer and it expands as the tree grows. Once the bark is older and tougher, it will no longer need protection.

How Do We Manage Fireblight

Colorado is said to be the worst state in the US for fireblight, and 2018 was considered by many to be one of the worst years in Colorado. Fireblight is a serious disease affecting apples, crabapples, pears, Mountain Ash and hawthorn, and sometimes quince and pyracantha (supposedly up to 73 species of plants).[Read More]

Biological Thinking

It has been suggested that this period of the 21st Century might well be called The Age of Biology, because the biggest challenges will be biological and the biggest breakthroughs will be in the realm of biology.

In this article, we will continue the discussion from the last issue on Biological Agriculture and Gardening, but this time going into specifics of biological thinking, biological discoveries and applications that improve plant and food success with biological solutions.[Read More]

Food Safety and GMOs

Food safety is one of the most critical issues of our time. What we eat is directly related to our health, and health care has a direct impact on our personal and national economies. Major chemical companies like Monsanto, Bayer, Dow and Dupont have introduced 86,000 synthetic chemicals into our environment, food, drugs, cosmetics etc and most of them have never been tested for toxic effects on human health and the environment. Since the mid 1990s, some of these same companies have been filling our grocery stores and feed stores with genetically engineered food products which may be causing serious health problems but are being approved by our government without safety testing.[Read More]

Invasive Plants and Weed Profiles

Last month we raised the issue of invasive introduced plants and the idea of being responsible gardeners who respect our native habitat and make an effort to not release invasive plants into the wild. We began with obvious noxious weeds that are having strong negative impacts on our native populations of plants and animals. This month again I am profiling weeds which have been declared as noxious, but this time a question is beginning to arise about under what circumstances are some of the less aggressive weeds invasive? In other words, is it possible that we might find a middle way that guides us strictly with the truly harmful invasives and more leniently with the less aggressive and more useful weedy plants? These are questions I am asking myself and will be asking in future interviews. We also welcome your views on this issue.[Read More]

Invasives August Issue

In February 2000 President Clinton established the National Invasive Species Council. Agriculture secretary Dan Glickman, Commerce Secretary William Daley and Interior Secretary Bruce Babbitt were asked to work together on a plan to minimize the economic, ecological and human health impact of invasive plants and animals not native to the US. The executive order on Invasive Species directs federal agencies to prevent the introduction of invasive species, to control populations of such species in a cost-effective and environmentally sound manner, to monitor populations, restore native species, conduct research and promote public education on invasive species.[Read More]

Invasives Intro

One of the hot subjects in horticulture these days is the issue of the invasiveness of introduced plants. Since they did not evolve here, they lack natural enemies, and whereas most are harmless, some have engulfed vast areas of wilderness, national forests, range and farm lands. This has led some people to campaign for “natives only” and others to attack the introduction of new plants as an ecological nightmare. In response to these attacks some in the plant industry have dismissed these fears as invalid over-reactions. As Colorado gardeners, most of us can be both excited by new plant introductions that are well-adapted to Colorado conditions, and feel very protective of our natural ecosystem and our native plants. In a series of articles, we hope to uncover some truths regarding these issues and to educate ourselves about how to work with this situation in a constructive manner.[Read More]

A Bad Year for Fire Blight

This is a bad year for fireblight which is a bacterial disease which affects mostly apple, pear, crabapple, hawthorn and Mt. Ash. It is spread in the presence of moisture and enters the trees through wounds and open blossoms. Colorado is the worst state in the US for fireblight.

Because of our moist spring and extra wounding caused by hail, there is a lot of infection. Symptoms include black, hooked twig ends, brown or blackened leaves, dried up fruits and sunken cankers that can be a dull orange or black. Fireblight is a difficult disease to manage because there is no cure. Spraying chemicals is not recommended by CSU because they are not very effective, timing is critical and spraying must be repeated.[Read More]

Fireblight: How to recognize it and deal with it (1997)

One of the most damaging and most perplexing diseases of the Front Range is fireblight. It is a bacterial disease affecting apples, crabapples, pears, Mt. Ashes, pyracanthas, quinces, hawthorns and occasionally cotoneasters. Fireblight does not affect cherries, plums, peaches or shade trees.

When the bacterium with the lovely name Erwinia amylovora enters the trees through an opening such as a wound, a pruning cut, the open blossom or leaf pores, the tissues quickly die causing blossoms and leaves and young twigs to suddenly wilt and turn black as if scorched by fire (hence the name “fireblight”). As the bacteria spread through the tissues, secondary infection continues through the season and bark areas die, become sunken and turn black or reddish-orange. These areas are called “cankers”. Sometimes large numbers of leaves turn black but the infection stays confined to small twigs; sometimes entire large branches die; occasionally the entire tree will die.[Read More]

Japanese Beetle is Here

Japanese Beetle is one of the most damaging insect pests in the Eastern and Midwestern US, but until recently, Coloradans were spared that challenge. It entered the US in 1916, but took until 2003 before a population was established in Colorado. This first infestation was in the Palisade area on the Western Slope. Even though eradication efforts were mostly successful there, established populations have been found since 2005 in Pueblo, southern Denver, Englewood, at DU and at Denver Botanic Gardens. Populations are being seen now in Boulder and Jefferson County.[Read More]

Managing Grasshoppers without Poisons

Nolo Bait is not a poison. It is a parasite that only affects grasshoppers and Mormon Crickets. It will not harm people, pets, wildlife or beneficial insects. It is most effective on small grasshoppers. In 3-4 weeks up to 50% of the grasshopper population will die. In addition, their eggs will be infected for the following season, and because grasshoppers are cannibalistic, they spread the disease. Put out shallow trays of the bran bait in small quantities. Wind, rain and contact with soil organisms can reduce bait available to grasshoppers.

Ducks, chickens, turkeys and guinea fowl can significantly reduce grasshopper populations. They must be fenced and put inside a safe structure every night to protect them from predators. They will also eat some plants, like vegetables.[Read More]

Managing Weeds Organically

Corn Gluten: made from corn it functions as an organic weed-and-feed. It works by keeping all seeds from germinating. Once a plant (or weed) begins to grow the Corn Gluten will not harm it. Very effective when used twice a year, in October and February. The effect lasts 6 months. The feed part is the 9% nitrogen fertilizing effect which thickens grass and stimulates the growth of all plants.

20% Vinegar: this natural acid will burn plant tissues it is sprayed on. Best to apply in bright sunlight and hot days. Spray thoroughly. Very effective on annuals; perennials may need more than one application. Be careful not to overspray on desirable plants as it is non-selective. Repeated use can acidify soils which in our alkaline soils is not usually a problem except for alkaline-loving plants like lilac.[Read More]

Pest Management for Bees

Overview: The Good News: 100,000 insect species; only 200 pests. We do not need neonics or any toxic pesticide to grow plants well. The solution is human attention, biodiversity, nutrient-dense soils, application of nontoxic management, and tolerance.

The Bad News: Most people and most nurseries don’t know the good news. They believe the chemical companies that we need to fear and attack insects and fungi as enemies.

More Good News: The concern of ordinary citizens who call nurseries and businesses and ask them if they are using systemic neonic poisons in their plants, is having a powerful effect. These companies now know we care and will buy plants that are neonic-free if we can. This could get them to change.[Read More]

Pyrethrum Insecticides: Are they Safe?

Pyrethrum is one of the best known botanical insecticides, effective against a wide variety of insect pests and generally considered safe to use. Is it really safe? To answer any question about pyrethrum it must first be explained that what is referred to as “pyrethrum” can be many different products. There is pyrethrum, the raw flowers; pyrethrins,the extracts from the flowers; and pyrethroids, synthetic pyrethrum. In addition many other insecticides and enhancers are often added to formulations which are called “pyrethrum”.[Read More]