Plant Pathology... what's it good for?

Whenever I'm out and about in the streets of Ottawa, I frequently bump into people who ask what I do for a living. The first words out of my mouth are invariably, "I'm a plant pathologist." The response this statement elicits varies: I've been asked if this means I'm a tree doctor. Others ask if I'm a landscaper.

One way I get around this is by asking them if they have a garden, lawn or tree with spots on the leaves. Then I ask what they do to prevent the spots from spreading - a very common answer was to spray the affected areas with a general-purpose pesticide. From this, I explain that if they were to have someone like me look at their affected plants/lawn/trees, they could probably get away without using general-purpose pesticides (which aren't very effective in many cases), or with a very minimal application of a specific pesticide targeted to the disease. At this point, they become highly interested because nowadays, no-one likes having to use pesticides, either self-applied or commercially applied.

It's interesting though, because the point here is that although people have a heightened awareness of the environmental and health implications of pesticides, few seem to have an awareness of what could be done to help reduce their use. One has to go to the source of the need for these pesticides - disease and insect pests - in order to determine the need for chemicals. Excess pesticide use in the past has already forced many of the causal agents to develop resistance, so other methods are needed.

A few key points to remember are:

1. if it's a plant, remove affected parts, clean the plant litter off the soil surface, ensure proper watering and fertilizing regimes are in place, and many insect pests can be taken care with a dilute solution of water and biodegradable soap;
2. if it's your lawn, ensure you know what you're looking at - dog urine causes nitrogen burns which look like a disease, june bug grubs are also major causes of lawn damage, fairy rings and mushrooms are caused by overwatering - many dead areas, if caught early, can be taken care of by replacing the sod in that area;
3. if it's your tree (i.e. a maple or crabapple tree) many leaf spots can be reduced in the following year by ensuring the leaves are raked and any fruit has been discarded of.
4. try a biological remedy. Many biological control agents are becoming available off-the-shelf at gardening outlets.

Some of these items can be reviewed on my other blog entitled Plant Doc, What's Up?

However, the situation becomes more complicated where large agricultural operations with monocultures of genetically homogenous plants are involved. The uniformity of the population generally means that there's lots of food for the pathogens and insects! In these cases, a rigorous integrated pest management (IPM) program coupled with a good integrated nutrient management program can reduce losses and avoid complications arising from changing environmental/agricultural legislations and policies.