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Pesticide Use Information for New York State | |
NAPIAP Survey - Field Corn - 1994 | |
Herbicide Use |
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New York weather is favorable for weed development, and weed pressure is extensive in almost every crop grown in the State, especially field corn. Since weeds often harbor insects and pathogens as well as significantly reducing crop yields through competition for site and nutrients, their presence in crop settings cannot be tolerated without substantial crop loss (Long Range Plan, 1992). In the 1970s, herbicide use to control weeds expanded due to:
Table 6 shows the percent of total acres planted to field corn grown for grain that was treated with herbicides in New York State in 1994. Ninety-nine percent of the grain acreage in this survey was treated with herbicides, ranging from 98.8% in the Southern Tier to 100% in the Hudson River area.
Ninety-nine percent of the total acres planted to field corn for silage was also treated with herbicides in 1994 (Table 7). However, two growers in the Southern Tier did not use any herbicides on their 64 acres of silage corn, making the range of herbicide treatment 96.3% in the Southern Tier to 100% in the Upstate and Hudson River areas.
Table 8 shows a summary of herbicides used by New York State growers on corn grown for grain in 1994. Although atrazine (AAtrex) was used by the greatest number of growers (50.9%), pendimethalin was used on the greatest number of acres of corn for grain (54.1%), and the greatest amount of active ingredient applied (18,640.7 lbs) was a combination of atrazine and metolachlor (Bicep). There was a total of 49,603.9 lbs herbicide active ingredient applied to 11,860.2 acres of corn for grain making an average of 4.18 lbs ai/acre applied in 1994. The greatest amount of ai/acre was applied in the Upstate area (4.77 lbs) followed by the Capitol/Catskills area (4.4. lbs, Figure 2).
Table 9 shows who applied the herbicides, the application equipment used, the timing and method of application, and the basis for application of herbicide applied to field corn grown for grain in New York in 1994. Eighty- eight percent of the fields, and 84.5% of the treated acreage had herbicides applied by the grower. The application equipment used most often was a boom sprayer (95.3% of fields, 93.7% of treated acreage). Herbicides were applied pre-emergence on more than half of the fields and 64.3% of the acreage, and were broadcast almost exclusively. The most common reasons that herbicides were applied were "routine application" (49.8% of fields, 53.4% of treated acreage), and "presence of pest on the basis of scouting" (39.1% of field, 60.1% of treated acreage).
Table 10 shows a summary of herbicides used by New York State growers on corn grown for silage in 1994. As with corn for grain, atrazine (AAtrex) was used by the greatest number of growers (55.9%), and pendimethalin was used on the greatest number of acres of corn for silage (48.2%). In contrast to corn for grain, the greatest amount of active ingredient applied (4,760.0 lbs.) was pendimethalin (Prowl). There was a total of 21,909.7 lbs. herbicide active ingredient applied to 6,137.6 acres of corn for silage making a total of 3.57 lbs. ai applied per acre in 1994. This is almost three quarters of a pound of herbicide active ingredient less per acre on corn for silage than on corn for grain. The greatest amount of ai/acre was applied in the Catskills/Capitol area (6.34 lbs/acre) followed by the North Country (4.30 lbs/acre, Figure 3).
Table 11 shows who applied the herbicides, the application equipment used, the timing and method of application, and the basis for application of herbicides applied to field corn grown for silage in New York in 1994. Eighty-eight percent of the fields, and 92.1% of the treated acreage had herbicides applied by the grower. Other than not specifying type of application equipment, all herbicides on corn for silage were applied with a boom sprayer. Almost one-half of the fields and over one-half of the acreage had herbicides applied preemergence and more than 91% were broadcast. The most common reason for herbicide applications on corn for silage was "routine application" (52.4% of fields, 49.8% of acreage), followed by "presence of pest on the basis of scouting" (30.8% of fields, 39.3% of acreage).
A cost comparison of herbicides used in field corn production is shown in Table 12. Because the average amount of active ingredient rate per acre is based on what growers indicated they used on their surveys, some of the costs per acre per application may not be exact. It is easy to see, however, why atrazine is so widely used. The cost per acre per application makes it an attractive herbicide, especially if a grower has many acres to treat.
Table 13 shows a comparison of rotation on the percent of field corn acres treated with herbicides in New York in 1994. As expected, there appears to be little difference in herbicide treatments due to crop rotation for corn grown for grain, or corn grown for silage. However, pounds per acre of herbicide active ingredient appears to be affected.
Figure 4 illustrates pounds ai/acre applied to corn by rotation. Third year and continuous grain corn had 4.6 and 4.35 lbs ai/acre applied versus 4.05 and 3.65 lbs ai/acre for first and second year corn, respectively. The difference is even more dramatic for corn grown for silage. First and second year corn had only 3.13 and 2.73 lbs ai/acre applied, while 3.6 lbs/acre were applied to third year corn and 4.25 lbs/acre were applied to continuous corn.
Table 14 shows a comparison of type of tillage used on the percent of field corn acres that were treated with herbicides. As expected, 100% of the no-till acres for both grain and silage, were treated. Growers who grew corn for grain using no-till applied only 2.33 lbs ai/acre, versus 4.0 for conventional and 4.74 for conservation (Figure 5). The same is true for corn grown for silage: 3.07 lbs ai/acre for no-till, 3.13 lbs/acre for conservation and 4.25 lbs/acre for conventional. The low number of growers in this survey using no-till systems is probably the reason for lower herbicide rates in no-till systems versus conventional practices.
Table 15 shows the type of weeds for which New York State growers treated corn for grain in 1994. The Table shows only the seven most commonly used active ingredients. Annual broadleaves were the major weed problem followed by annual grasses. The perennial grasses and broadleaves were of little importance for most of the acreage. Table 16 shows the same information for corn grown for silage. Again, annual weeds were of the greatest importance, and perennial weeds were of the least.
Figure 6 illustrates the percent of acreage treated with herbicides for specific weed types by area of the State. Corn grown for grain (Figure 8) in the Catskills/Capitol area had a much greater problem with perennial grasses than in the other regions, and the Southern Tier and Upstate areas treated more acreage for annual grasses than either the Catskills/Capitol or Hudson River areas. Sedges and annual weeds were a big problem in the North Country in corn grown for silage, while perennial broadleaves were more of a problem in the Hudson River area.
The effect of rotation on types of weeds treated for is illustrated in Figure 7 for both corn for grain, and corn for silage. Third year corn appears to have a bigger problem with triazine resistant weeds and perennial grasses in corn grown for grain. Less than one-third of the corn grown for silage, regardless of rotation, was treated for anything other than annual weeds.
Finally, the effect of tillage system used on types of weeds treated for is illustrated in Figure 8. In both types of corn, perennial grasses appear to be a major problem in no-till corn, while annual weeds are a minor or non- existent problem. This makes sense as perennial weeds tend to build up in no- till fields.
