Teaching apple growers to monitor populations of orchard pests and use a variety of non-chemical controls before turning to pesticides—a practice called integrated pest management (IPM)—has saved New Hampshire growers at least $7.7 million in spraying costs over the past 25 years. Adopting IPM practices has allowed growers to cut the number of pesticide sprays in half, while increasing the percentage of high-value, unblemished fruit by 1.1 million bushels.

UNH Cooperative Extension entomologist and IPM coordinator Alan Eaton recently released a report that documents the extraordinary success of the apple IPM program he has coordinated for 25 years. From its beginnings in 1978, when a handful of growers agreed to test IPM techniques on a few trees in their orchards and compare results with conventional practices, the program has proven so successful that all of the 2500 acres of commercial orchards remaining in New Hampshire now use it.

Then and now

Twenty-five years ago New Hampshire boasted 5500 acres of commercial apple orchards. The standard apple trees of the day stood up to 30 feet tall and 35 feet wide at the crown. It took about 300 gallons of spray per acre and growers sprayed on a schedule to combat the numerous insect, disease and weed pests affecting apples. Even then, they found pest damage on 10 percent of their fruit significant enough to lower its value.

Today’s orchards feature plantings of much smaller dwarf or semi-dwarf trees half the size of the old standards. Expanding world apple production and other market factors have cut in half the acres of commercial apple production in New Hampshire and reduced apple production by half a million bushels. Most growers today market their apples and apple products directly to retail outlets or consumers.

Instead of spraying according to a pre-determined schedule the way they once did, growers using IPM techniques learn the life cycles of pests and the conditions that favor them, monitor the emergence of various pests by setting out a variety of traps and lures, scout their orchards for visual evidence of pests, and call to Eaton’s IPM hotline, updated weekly, so they can time their sprays accordingly. Despite the pesticide reductions, less than five percent of their apples show pest damage.

Although apple growers have cut the number of times they spray each season by half, Eaton says most of them probably spend about as many hours on the computer or out checking traps as the previous generation of apple growers spent preparing sprays and sitting on a tractor spraying their trees.

Building the program

To build the IPM program, Eaton and colleagues made site visits, wrote fact sheets, held winter workshops, organized on-site twilight meetings, and presented at grower meetings to recruit participants and disseminate information. Eaton says the IPM program has involved an intense partnership between Extension field staff, support staff, graduate students, summer assistants, private consultants and growers themselves, not only in New Hampshire, but regionwide.

He collaborated with specialists from throughout New England to produce the New England Apple Spray Guide (which grew from a 19-page spray schedule to the sophisticated 161-page guide that gets updated every two years). He promoted the introduction of nest boxes and perches for hawks and owls to reduce populations of mice and voles in orchards, and released populations of predatory insects and parasites that prey on apple pests.

Other benefits

Eaton says the apple IPM program has delivered benefits beyond the actual cost of fewer sprays:

• It has reduced the risk of adverse health effects from pesticides on farmers, farm workers and farm families.
• It has reduced the risk of pesticides contaminating ground and surface waters.
• Spraying less extends the life of expensive spraying equipment, lowering operating costs.
• It has increased populations of beneficial insects and parasites around apple orchards.

Eaton also knows of instances where he believes “IPM savings have been so substantial that it kept businesses afloat during difficult times,” thought he hasn’t tried to quantify jobs saved or growers able to stay in business.

He says his report serves as only “a rough look at the program and its impacts. It isn’t a complete economic analysis. For one thing, I haven’t ‘translated’ the dollar impacts from early years into 2004 dollars. For another, I haven't decided when to stop counting some impacts. 

“In response to the IPM work, growers cut their spraying by nearly one-third in the first five years of the program. Certainly no one would spray the old way today. Do we keep counting that as valid spray reduction this year? When do we stop counting? I don’t know.”

For more information  

• UNH Cooperative Extension IPM Program
• Northeast Region IPM Center website   Developed and maintained collaboratively by Extension IPM throughout the Northeast. Links to every Extension IPM program in the Northeast region..  You can also use the search engine on the site, to search only public IPM sites for information (and avoid a lot of sales pitches).
• Univ. Massachusetts Fruit Advisor Aimed at commercial fruit growers, it offers newsletters and publications