Organic, Integrated Pest Management (IPM) and Conventional Agriculture: What are the differences?

by Bill Duesing

A recent study found that many people think that all local food is organic.  Others assume that all CSAs are organic, or that all the products at a farmers market are organic, or that IPM and organic are the same. None of this is true. And there's lots of confusion.

The Vegetable Management Guide for the New England Region provides much useful information not only for anyone who grows vegetables, and also for those who want to understand the differences between conventional, IPM and organic methods and produce. (The color photos of pests and diseases alone warrant a visit for anyone who grows vegetables or strawberries.)

The Guide is updated and published two years by the Cooperative Extension Services in the six New England states. A comprehensive guide for commercial vegetable growers, it is available free electronically or as a hard copy for a fee. Click here for details.

The Guide is intended for use by both organic and conventional growers.  It provides encouragement for conventional growers to use IPM practices, many of which can also be used by organic growers.

The authors include agricultural professionals in the region's Land Grant college system, the Universities of Connecticut, Massachusetts, Maine, New Hampshire, Rhode Island and Vermont.  Many of these authors have shared their knowledge at NOFA conferences and farm tours, as well as directly with organic farmers. (If we are going to ramp up our local food production, we'll need to support this important research, education and extension system that has seen diminishing funding for decades.  The Guide was brought to my attention by a notice from UConn stating that the only extension professional available to visit Connecticut's commercial vegetable growers and provide appropriate advice for conventional and organic growers is on extended medical leave and will be unavailable this summer.  The notice provides links to helpful resources including organic ones.)

The section of the Guide on cultural practices contains information on soil testing, nutrients, compost, cover crops, rotation and more.  Unfortunately, there is little information about soil biology.  (See last month's blog for soil biology resources.)

There is a section on Organic Certification and a helpful list of fertilizers approved for organic production. Other sections include crop rotation, cover crops, irrigation, raised beds, insects that can be controlled by row covers and a guide to estimating vegetable yields.  There are contacts in each state for organic certifiers, soil testing labs and plant diagnostic facilities.

Well over half the Guide is devoted to varieties, care, and control of crops, with listings covering vegetables from asparagus to zucchini. (The latter is covered in the pumpkin, squash and gourd section.) For each vegetable or family, there is a list of suggested varieties as well as basic planting, fertilizing and harvest information. 

Most of each listing contains information about pests that bother specific crops and the pesticides (i.e., herbicides, insecticides and fungicides) that can be used for controlling weeds, insects and diseases. 

For snap, dry and lima beans, there's about a page of general variety and cultural information and more than six pages devoted to pests and controls. Under weed control, there are sections for pre-planting, stale seedbed, at-planting and post-emergence weed control. There are even several herbicides used to defoliate dry beans. This information is critical to conventional growers, since the wrong herbicide can injure that crop or a succeeding one. Some herbicides for snap beans will hurt lima beans. Others are for dry beans only. It is very tricky to sort the crop plants from the weeds with chemicals. (All the more reason to grow organically, don't you think?)

The insect control section lists products for each different insect.  There are aphids, cutworms, European corn borer, corn earworm, cabbage looper, garden springtails, leaf hoppers, Mexican bean beetles, seedcorn maggot, two-spotted spider mite, tarnished plant bug and slugs.  Despite their names, these are all bean pests. 

For diseases, there are suggested materials for treating anthracnose, downy mildew, bacterial blights, bean common mosaic virus, bean yellow mosaic virus, rust, seed decay and white mold.

This Guide provides many important cautions.  Some products are dangerous to bees and can't be used where they are foraging; others can't be grazed by livestock, can't be cultivated so many days before use, or need to be incorporated to be effective.  Other cautions include "doesn't control lambsquarters post emergence ... don't apply in the midday sun ... don't apply more than once ... apply at seven to 14 day intervals ... and apply between midnight and dawn."

Eight tenths of an ounce (0.8 oz.) 

barely covers the bottom 

of a measuring cup. It is less than 

two tablespoons.

Many of the products listed are very powerful chemicals.  Some are used at the rate of only a few ounces per acre. One pesticide for cutworm control is used at just eight tenths of an ounce per acre (sprayed between midnight and dawn). It has a 12-hour restricted entry interval and a seven-day wait until harvest!  It is amazing that less than an ounce of this product, diluted with water and spread over 43,560 square feet provides control.  And it is scary that so little product creates conditions which prohibit entry for 12 hours and food too dangerous to eat until seven days later.

If you are interested in doing more research about pesticides visit this site. For example, search for cyfluthrin, the active ingredient in the cutworm control above and look at the wide variety of information there, including its highly toxic nature to a number of living things.

The Guide provides copious information about rotating among groups of pesticides in any category so that diseases, insects or weeds don't develop resistance.  (The super weeds created by the genetically-engineered Roundup Ready® system are a classic example of how Nature always finds a way to thwart repeated applications of the same pesticide.) 

If the Guide dealt solely with organic materials and methods, it would be much shorter.

Of the 132 pesticide listings in the bean section, only 14 are identified as OMRI (Organic Materials Review Institute) listed, which means they are approved for use on organic farms. (These numbers are from my 2008-2009, hard copy edition of the Guide. Certified growers should check with their certifying agent about any specific products. Listings and usage change.  For any pesticide, even organically-approved ones, the label is the law.)

Since some products can control a number of pests, there are only seven different organic pesticides listed.  One is a clay, one a mineral, three are derived from soil organisms and two are derived from plants. All but one have zero days wait before harvest. 

IPM

Since nearly everyone (with the possible exception of pesticide producers, marketers and lobbyists ) has an interest in reducing pesticide use for economic, agronomic, human health and/or environmental reasons, there is a very useful section on Integrated Pesticide Management. 

According to the Guide, IPM "is the coordinated use of pest and environmental information to design and implement pest control methods that are economically, environmentally and socially sound.  IPM promotes prevention over remediation and advocates integration of multiple control strategies to achieve long-term pest management solutions."

For about four decades, entomologists and ecologists have advocated IPM as a replacement for the calendar spraying (e.g., application of a chemical every 10 days from July to harvest)that used to be the norm and unfortunately still is in some cases.  In contrast, IPM encourages growers to create growing conditions that favor healthy plants, carefully monitor crops for damage, determine that damage will have an economic impact, and then use that information to decide on a control strategy. 

Accurate pest identification, an understanding of the pest's biology and life cycle, and scouting the crop for the pest or its signs are part of the process.  Monitoring can be of weather conditions or the pest insects caught in a trap which is baited with an attractant.  All this data is combined with good records of past seasons and known action thresholds to inform decision-making and management strategies. Examples of action thresholds are if so many insects are counted per plant or a certain percentage of the crop has been damaged.

A complete IPM management plan includes a hierarchy of controls.  Four of the five levels  apply to any farm or garden, organic or conventional.  They are: 

1.    Cultural controls, such as building soil health, proper spacing and rotations or adjusting planting times to avoid insect pressure.

2.    Mechanical and physical controls such as cultivation or mulches to control weeds or row covers to exclude insects.

3.    Genetic controls including selecting varieties that grow well in your area, that are resistant to specific diseases or less affected by a pest insect.

4.    Biological controls which involve encouraging or releasing beneficial or predatory organisms including beneficial insects, mites, spiders, nematodes, fungi, bacteria, viruses, protozoa and plants.  This even includes the use of trap crops and microbial pesticides such as the organic ones mentioned above that come from soil organisms.

It is primarily in the last stage of control - pesticide use - that organic and conventional IPM growers diverge.  A conventional grower using IPM techniques has a much wider array of generally more toxic, synthetic products to chose from as a last resort. 

Although IPM is encouraged by most or all agricultural professionals and embraced by many farmers, it is a system without any regulation.  Also, just because a farmer says he or she practices IPM, there is no guarantee that conventional pesticides weren't used.  At this point, any farmers who don't use IPM are way behind the times and are missing an opportunity to protect the health of workers, ecosystems and themselves.

The Guide helps us understand the differences between organic, conventional and IPM methods of growing produce and provides a window into the complexity of farming.  It also exemplifies why many organic farmers just say no to pesticide use and concentrate instead on creating conditions which support soil, plant and ultimately human health.

Look for local Certified Organic, CTNOFA Farmers Pledge and exempt organic produce. An exempt organic farm follows organic standards and sells less than $5,000 worth a year.

Here is an additional resource from UConn's web site.