Tag Archives: Deborah Henderson

Surviving a Municipal Cosmetic Pesticide Ban: New products

Trichoderma—the greenish fungi growing in circles on the special selective pink agar—recovered from leaves of plants treated in a 2012 field trial. Photo courtesy Deborah Henderson


By Deborah Henderson, PhD

Some new fungicide products are becoming available to help control soil-borne diseases. One registered now in turf is a bacterium (Bacillus subtilis, Rhapsody) for controlling a broad spectrum of bacterial and fungal diseases of turf including Brown Patch, Anthracnose, and Dollar Spot. A second is a fungus (Trichoderma harzianum, Rootshield) that has not yet been registered for turf, but controls soil-borne diseases in ornamentals.

A reality check for all new biological and low-risk pesticides is they do not work like chemical pesticides. This author suggests paying more attention to the label instructions; do not wait until a pest or disease is epidemic, take a proactive approach. As a pest manager, you need to know more about your system as well as these new products. Small-scale ‘trials’ with any new product are a great way to get some experience with them.

Some new low-risk herbicides seem to work well and others are more fussy about how they are used. Get to know them. Even if a product does not work for you in some situations, it may work quite well in others, so it is important not to give up until it has been tried a few times in different conditions. To get the best out of new soft products, they need the best chance for success. These are your new tools and they will perform best when used within IPM strategies where you employ all available tactics to suppress weeds, pests, and diseases.

Read the full article: Surviving a Municipal Cosmetic Pesticide Ban

Surviving a Municipal Cosmetic Pesticide Ban: Controlling pests with nematodes

Two Galleria melonella insect larva. The red one has been infected by the nematode Heterorhabditis bacteriophora, and infection caused the larva to turn this characteristic red colour. The white larva is uninfected. This insect is not a pest of turf, but a lab-reared insect commonly used to study insect pathogens. Photo courtesy Deborah Henderson


By Deborah Henderson, PhD

Nematodes are microscopic ‘worms’ that do not require registration in Canada as a pesticide, and control soil-dwelling insects. There are two groups (i.e. genera) available commercially that can be quite useful. Numerous suppliers provide nematodes of various species and some have pest specificity, so one should check the labels.

One genus, Heterorhabditis (i.e. H. bacteriophora, H. megidis, and H. marelatus), finds its prey in the soil by using a ‘seeking’ predator strategy, actively moving about in the soil searching out prey. The other genus, Steinernema, is a smaller nematode (i.e. S. carpocapsae, S. krausii, and S. feltiae) that uses an ‘ambush’ strategy, waiting for hosts to come along then latching on.

Nematodes find natural host orifices and burrow inside to grow, mate, release insect toxins and produce young. The host insect turns a characteristic colour and dies. The juvenile nematodes burst out of the dead insect and start their search in the soil to find another host. While an application of nematodes will result in some being present in the following year, the concentration is not usually high enough to provide a second year of control for a pest that annually invades turf or ornamentals.

Read the full article: Surviving a Municipal Cosmetic Pesticide Ban

Surviving a Municipal Cosmetic Pesticide Ban: Using low-risk herbicides

Nematodes are being applied to control European Chafer on a home lawn. Photo courtesy Deborah Henderson


By Deborah Henderson, PhD

There are three basic modes of action for low-risk herbicides:
● killing or ‘burning’ down top growth with no effects on roots;
● inhibition of seed germination; and
● attack with a plant pathogen (i.e. biological control), killing all parts of the weed.

The first two modes of action are familiar to those using chemical herbicides, but the third is new. Biological controls for weeds are pathogens that live by feeding on the weed. They tend to be very specific for certain types of plants and require specific environmental conditions. Though a bit fussy about their conditions, these controls can work extremely well.

Read the full article: Surviving a Municipal Cosmetic Pesticide Ban

Surviving a Municipal Cosmetic Pesticide Ban: Pesticide risks

By Deborah Henderson, PhD

Since 2003, there has been a big increase in availability of low-risk or ‘soft’ products in the market, fuelled largely by cosmetic pesticide bans. It should be emphasized ‘soft’ and ‘low-risk’ do not imply ‘no risk.’ One should not be fooled into thinking these products have no toxicity for your family or pets. They are environmentally protective, and less toxic than those they replace, but they should be treated like the chemicals they are. They need to be kept out of reach of children and pets, users should wear protective gear if the label directs, and any ‘re-entry’ interval instructions must be observed.

Most new products for use in municipalities with bans are on B.C.’s “excluded pesticide” list (the fifth and lowest risk category).

Read the full article: Surviving a Municipal Cosmetic Pesticide Ban

Surviving a Municipal Cosmetic Pesticide Ban

By Deborah Henderson, PhD

Managing pests, diseases, and weeds within cosmetic pesticide bans can be a challenge. Every municipality has different rules and even provincial bans regulate in dramatically different ways across the country. While most people understand and agree with the concern about overuse of pesticides and protecting the environment and their health, the turf industry is also faced with maintaining rather high standards for the cosmetic value of landscapes and a very real gap between what is expected and what is possible. It is difficult to be the bearer of bad news.

Whether provincial or municipal, the recurring themes of Canadian legislation is to ban:
● active ingredients;
● products based on their use patterns; or
● products based on concentration or package size.

Read the full article: Surviving a Municipal Cosmetic Pesticide Ban