Table 1. Number of suvey respondents by
District of residence, 1998 Idaho wheat
IPM survey

• The typical grower annually farmed a total of 1175 acres averaged across all field and row crops (TABLE 2). The minimum reported total acres farmed was 50 acres and the maximum reported was 17,000 acres. Average total acres farmed was smallest in Districts 3 and 4 (789 and 996 total acres, respectively) and largest in District 5 (1690 acres).

• Soft white winter wheat and soft white spring wheat were the predominant market classes among growers surveyed (FIGURE 2); together they accounted for nearly 70% of total statewide wheat acres planted by respondents. Average annual statewide production of soft white wheat ranged from 200 to 250 acres planted per grower; soft white winter wheat field size tended to be larger than soft white spring wheat field size (TABLE 2).

• Only in District 5 did soft white wheat comprise less than a majority of total wheat acreage (FIGURE 3); here hard red spring and hard red winter wheats together were 68.3% of wheat acres planted. Field sizes too were larger in District 5 than in other regions (TABLE 2); each District 5 grower planted on average 325 to 500 acres of hard red wheat.

• Soft white and hard red wheats were produced in all 5 production districts, but other wheat classes were limited to certain districts. Hard white spring wheats only were reported from Districts 4 and 5, club wheat was limited to Districts 1 and 2, and durum wheat only was reported from District 2 (FIGURE 2).

• Overall, 47% of growers said their wheat production was not irrigated. Dryland (non-irrigated) production predominated in Districts 1, 2 and 5 and irrigated production was the norm in Districts 3 and 4 (TABLE 2).

• On average, survey respondents were 46 to 55 years old, they had completed some post high school vocational training or college coursework, and generated gross farm sales of $100,000 to $250,000 annually.

• Essentially all Idaho wheat producers (mean = 96%, range among districts = 92 - 98%) plant weed-free (certified) seed on more than half their commercial wheat acreage.
  

• Between 60 and 70% of Idaho wheat growers statewide plant pest-resistant wheat varieties and rotate wheat with non-cereal crops on more than half their wheat acreage to reduce pest infestation levels. But usage patterns differed among Districts. In general, pest resistant varieties are used by fewer growers in the irrigated production systems of southern Idaho (Districts 3 and 4); here 50 to 60% of growers plant resistant varieties on more than half their acreage. In contrast, about 75 to 90% of growers in Districts 5 and 1 plant pest-resistant varieties on more than half their acreage. Rotational schemes showed the opposite pattern: longer rotations out of wheat and other cereals in Districts 3 and 4 and shorter rotations in Districts 1 and 5. Approximately 50 to 75% of producers follow at least a 3-year rotation out of cereals in Districts 3 and 4, compared with about 20 to 35% in Districts 5 and 1, respectively. Southeast Idaho (District 5) was the only region where fewer than a majority of growers (28%) said they rotated to non-cereals on more than half their acreage.
  

• About 1 in 3 wheat producers statewide manages disease, insect, nematode or weed problems by adjusting planting or harvesting dates, seeding rates, or row spacing on more than half their wheat acreage. Survey respondents in District 5 were less likely to use these practices than producers in other Idaho production regions; 22% of growers there said they control pests by adjusting planting or harvesting dates, seeding rates, or row spacing on more than half their wheat acreage.
  

• About half of the growers in irrigated production districts said they adjust irrigation timing or amount for pest control on more than half their wheat acreage.
  

• Fewer than 10% of wheat producers statewide said they control pests by burning wheat stubble after harvest on more than half their acreage; 65% reported that they never burn wheat stubble. Regional incidence was as follows: 
  

  	% growers
  District 1	5
  District 2	3
  District 3	3
  District 4	7
  District 5	17
  mean	7%

  where values are percent growers who burn stubble on more than half their acreage.

Table 3A. Percentage of Idaho wheat growers using IPM
practice on more than half their wheat acreage on average
during the past 5 years.

• About 1 in 3 growers reduce insecticide use to protect beneficial predatory and parasitic insects; about 1 in 5 growers said they scout fields for beneficial natural enemies.

• Direct management of biological agents for pest control is virtually untried among wheat producers. Only 1 to 2 % of growers reported that they deliberately create habitat reservoirs for beneficial natural enemies, provide natural enemies with supplemental foods and attractants, or purchase and mass-release agents.

• About 8 wheat growers in 10 use field scouting and thresholds to determine the need for pesticide applications on more than half their wheat acreage. The incidence of field scouting for weeds and insects (aphids) was similar among the five production districts. Producers in Districts 3 and 4 were more likely to take soil samples for nematodes than growers in Districts 1, 2 and 5.

• More than 60% of the growers said their wheat fields are checked at least weekly during the growing season for diseases, nematodes, insects or weeds. Fewer than 20% said they only check their fields once or twice seasonally. No grower reported never checking their wheat fields for pests.

• A minority (14%) of growers statewide use forecasts from the aphid suction trap network to determine safe (aphid-free) planting dates on more than half their wheat acreage, but there were substantial differences among regions -- nearly 40% of District 5 survey respondents said they use suction trap forecasts, compared with 2-11% elsewhere

• Few producers (11%) hire consultants for IPM scouting services. The Idaho wheat industry is just beginning to use "high-tech" pest monitoring systems

• 70% of growers statewide consider risk of groundwater contamination when selecting pesticides.

• Four in nine growers rotate pesticide classes on half or more their wheat acres to avoid the development of resistance.

Table 3B. Percentage of Idaho wheat growers using IPM practice on
more than half their wheat acreage on average during the past 5 years.

• Essentially all wheat acreage is treated with herbicides, particularly post-emergence herbicides for broadleaf weeds.

• Statewide insecticide use is limited to approximately 40% of the wheat acreage annually. Further, of the acreage treated with an insecticide, 92% receives a single insecticide application yearly. Foliar insecticides applied after wheat emergence are used on 3-times the wheat acreage as soil insecticides applied before or during planting. Yet overall statewide use of foliar insecticides is low; less than 25% of wheat acreage is treated with foliar insecticides.

• Idaho wheat producers rarely use soil fumigants and nematicides; less than 5% of the wheat acreage is treated with these pesticides.

• Wheat growers seldom make repeated pesticide applications to the same field during the season. None of the 183 growers surveyed applied more than one application of a nematicide or soil fumigant. Less than 5% of the wheat acreage annually receives more than 1 application of foliar fungicides or insecticides. Herbicides as a class are more frequently applied several times to a single field during the season; 20% of the acreage statewide is treated with 2-3 herbicide applications each season, while 4% receives 4 or more herbicide applications.

• Herbicide and nematicide use generally is similar among wheat production districts (FIGURE 4). There were greater differences among districts in use of chemical seed treatments, foliar fungicides and insecticides. Compared with statewide averages in TABLE 4, a greater-than-average percentage of wheat acreage in northern Idaho (District 1) is treated with chemical seed treatments, foliar fungicides and insecticides, while a smaller-than-statewide average percentage of wheat acreage in Districts 3 and 5 are treated with these pesticides.

Table 4. Statewide pesticide use patterns in wheat. Values are averages
reported by growers in response to the survey question, "On average during
the past 5 years, to what extent did you, or someone who works for you, apply
the following types of pesticides in your wheat acreage."

Figure 4. Regional pesticide use patterns in wheat. Values
are percentage of wheat acres receiving at least 1 application
on average each year.