Wildlife & Pesticides - Peanuts

Authors: William E. Palmer, Peter T. Bromley, and Rick L. Brandenburg

North Carolina Cooperative Extension Service AG-463-5

Wildlife is an important part of a healthy rural environment. This fact sheet is one of a series that describes how pesticides can be managed to minimize hann to wildlife on our farms, in our waters, and in our forests.

Wildlife is a valuable natural resource. Most farmers enjoy seeing wildlife on their farm, and many benefit economically by leasing hunting and fishing rights to sportsmen. In North Carolina, more than $1.1 billion is spent annually by hunters and fishermen alone.

Peanut fields provide both food and cover for wildlife. Quail and their docks, deer, rabbits, and other birds and mammals are attracted to peanut fields.

The value of these fields and surrounding areas as wfldlife habitats depends on the pesticides used during the growing season. Many birds can be lethally poisoned by cides applied to crop fields. SubledW poisoning can result in an animal becoming sick. Once sick, wild birds may neglect their youn& abandon their nests, and become more susceptible to predators or disease.

Most pesticides used on peanuts are not highly toxic to wildlife. However, these pesticides can affect wildlife indirectly by reducing their food and cover. Populations of gamebirds are reduced when herbicides and insecticides are intensively used. These pesticides can destroy brood cover and reduce msect and plant foods, lowering the survival rate of gamebird chicks.

Careful selection and use of pesticides, however, can lessen their impact upon wildlife. This publication (1) describes how pesticides used on peanut fields can harm wildlife and (2) describes how farmers can minimize adverse effects of pesticides on wfldlife.

Insecticides

Wildlife that live in and around peanut fields are exposed to cides when they eat granules or chemical residues on plants and in insects. Wildlife that enter fields soon after an insecticide has been sprayed are exposed when the insecticide contacts their skin and eyes or when they inhale the vapor.

Tables 1 and 2 list recommended in the North Carolina Agricultural Chemicals Manual for use on peanuts. Table 1 rates insecticides according to their toxicities to birds, mammals, and fish. The effects of pesticides on wildlife and fish can be minimized by using the least toxic alternative. Inseticides in Table 2 are rated low, moderate, or high based on the hazard their use presents to wildlife (birds and mammals). The hazard of an insecticide is based on its toxicitv to wildlife, the way it is used, and other characteristics, such as its persistence in the environment. For example, methomyl (Lannate) is acutely toxic to birds and mammals (Table 1). However, because methomyl does not persist in the field, careful use of this chemical presents only a moderate hazard to wildlife (Table 2). Wildlife exposed to insecticides rated high may die or become sick. Insecticides rated moderate may also cause death or sickness, although death is unlikely. Pesticides rated low are unlikely to harm wildlife directly.

Granular Insecticides

Granular formulations present a serious hazard to birds. Some highly toxic insecticides are formulated as granules; they include phorate (Thimet), disulfoton (Di-Syston), and ethoprop (Mocap). Birds eat granules exposed on the soil surface, mistaking them for food or grit. Ingesting only a few highly toxic granules can kill a small bird. Wildlife can also be poisoned by residues left on food items after granules dissolve.

To reduce the danger to wildlife from granular formulations:

Most pesticide labels require full incorporation of insecticide granules. Disking under granules spilled at row ends and field edges is especially important because birds look for food and grit in these areas. If soil incorporation is not possible, consider using a recommended liquid formulation following the guidelines in the next section.

Liquid Insecticides

The application of foliar sprays can harm wildlife, especially when highly toxic insecticides are allowed to drift into wildlife habitats or are sprayed directly onto wildlife. Waterfowl and gamebirds have been killed by aerial applications of toxic insecticides. Wildlife such as quail and deer are attracted to peanut fields during July and August when foliar insecticides are often applied.

Several studies of aerial applications of pesticides have reported significant drift of material into nearby wildlife habitats and ponds. If it is necessary to use highly toxic insecticides, apply them with ground equipment; this will help to minimize drift and reduce the hazard to wildlife. Ground application may also allow wildlife more time to leave the area during the spraying operation.

Spray drift can be minimized by using application equipment with low drift characteristics, replacing inappropriate or worn nozzles, using appropriate pressure and volume for the chosen nozzle, and adding a drift control agent. Ultra-low-volume sprays are more likely to cause drift than low pressure sprays. Of course, avoid spraymg when the wind is blowing faster than 8 mph.

Organophosphate insecticides are poisonous to wildlife, and their effects are additive. Thus, multiple exposure to these insecticides increases their harmful effects. Wildlife deaths are more likely to occur when these insecticides are applied at intervals of less than 10 days.

To reduce danger to wildlife from liquid insecticides:

Systemic Insecticides for Insect Control

Approximately 90 percent of peanut acreage is treated with at- planting systemic insecticides. However, some of these are highly toxic and have caused wildlife die-offs; these include phorate (Thimet), disulfoton (Di- Syston), and aldicarb (Temik). To reduce wildlife exposure to insecticides, try to plant resistant peanut varieties, such as NC6, which requires half the amount of insecticide that is applied to nonresistant varieties. Incorporation of granules ensures that wildlife poisonings will be minimized. Disking under granules spilled at row ends (where birds look for food) is important to avoid hazard to wildlife.

An alternative to treating fields with at-planting systemic insecticides is to scout fields for thrips and leafhoppers. This IPM practice can help to reduce costs without sacrificing yields. If a field has reached economic thresholds for pests, select a foliar insecticide that is not highly toxic to wildlife.

Granular Insecticides for Late-Season Insect Control

Granular insecticides are banded or broadcast over peanuts between June and August mainly for control of southern corn rootworm (SCR). Toxicity data suggest that using Lorsban will minimize hazards to wildlife. Avoid broadcasting granules that require higher rates of insecticide use (such as Dyfonate). Planting resistant peanut varieties, where possible, can reduce insecticide use by 75 percent. A banded application of Lorsban or Dyfonate by tractor in June, rather than July or August, provides season- long control of southern corn rootworm and makes incorporation of granules easier since the vines are small. This approach helps to reduce wildlife exposure by burying the granules and also increases the effectiveness of SCR control.

Table 1. Toxicity of Insecticides and Nematicides Used on
         Peanuts to Birds, Mammals, and Fish
__________________________________________________________
Pesticide (Brand Name)   Birds     Mammals     Fish
__________________________________________________________
acephate (Orthene)         M         L          L
aldicarb (Temik)           Hc        H          EH
carbaryl (Sevin)           L         L          H
chlorpyrifos (Lorsban)     H         L          EH

diazinon                   Hc        M          EH
disulfoton (Di-syston)     Hc        H          H
esfenvalerate (Asana XL)   L         L          EH
ethoprop (Mocap)           Hc        M          H

fenamiphos (Nemacur)       Hc        H          EH
fonofos (Dyfonate)         H         H          EH
malathion                  L         L          EH
methomyl (Lannate)         H         H          H

phorate (Thimet)           Hc        H          EH
propargite (Comite, Omite) L         L          H
________________________________________________________
Wildlife hazard is based on the following toxicities:
  H(highly toxic) = LD50 less than 30 mg/kg and/or
                    LC50 less than 500 ppm.
  M(moderately toxic = LD50 > 30 mg/kg and <100 mg/kg
                  and/or LC50 > 500 and < 1000 ppm.
  L(low toxicity) = LD50 > 100 mg/kg and LC50 > 1000 ppm.
  NT(Not toxic)

Fish 96-hour LC50 toxicities are as follows:
  EH(Extremely toxic) less than 0.1 ppm
  H(Highly toxic) 0.1 to 1.0 ppm
  M(Moderately toxic) 1 to 10 ppm
  L(Low toxicity) greater than 10 ppm

To convert fish toxicities to pounds of active ingredient
  per acre-foot of water, multiply by 2.7.

c= active ingredient (not necessarily a specific product)
   has caused wildlife deaths.




Table 2.Hazard of Insecticides Used on Peanuts to Wildlife.
________________________________________________________________________________________
                                          Wildlife
Insect          Insecticide (Brand Name)   hazard     Kills    Comments
________________________________________________________________________________________
Armyworm	acephate (Orthene)	  moderate	no	See corn earworm
		methomyl (Lannate)        moderate      no	comments.
________________________________________________________________________________________
Beet armyworm	esfenvalerate(Asana XL)	  low		no	Asana provides only fair
		methomyl (Lannate)        moderate	no	control.(see publication
								AG-331.) Applying
						                Lannate by air increases
						                hazard to high.
________________________________________________________________________________________
corn earworm	carbaryl (Sevin)	  low		no	Sevin and Asana XL are
		esfenvalerate(Asana XL)	  low		no	safer for wildlife. Orthene
		acephate (Orthene)	  moderate	no	is safer than Lannate,
		methomyl (Lannate)	  moderate	no	which is very toxic to
						                wildlife.
________________________________________________________________________________________ 
cutworm		carbaryl(Sevin) 	  low	        no	Diazinon is toxic to birds
		esfenvalerate(Asana XL)   low		no	and fish. Broadcasting
		diazinon 14G		  high		yes	granules increases
			                                        wildlife hazard.
________________________________________________________________________________________
Leafhoppers	carbaryl(Sevin) 	  low	        no	Asana XL it extremely
		esfenvalerate(Asana XL)	  low	        no	toxic to fish. Do not spray
		malathion		  low	        no	where drift may enter
		acephate (Orthene)	  moderate	no	ponds. 
________________________________________________________________________________________

Lesser  	chlorpyrifos 4EC(Lorsban) low	        no	Dyfonate is highly toxic to
cornstalk	chlorpyrifos 15G(Lorsban) moderate	no	birds. Use of Lorsban EC
borer		fonofos 20G (Dyfonate)	  high	        no	reduces hazard.
________________________________________________________________________________________
Southern corn	chlorpyrifos 15G 	  moderate	no	Fully incorporate all
rootworm	fonofos 10,2OG (Dyfonate) moderate	no	granules. Broadcasting
		ethoprop 10, 15G (Mocap)  high	        yes	granules increases
		phorate 15G (Thimet)	  high	        yes	wildlife hazard.
________________________________________________________________________________________
Spider mites	propargite (Omite, Comite)low	      no	Propargite is toxic to fish.
________________________________________________________________________________________
Thrips	        cabaryl (Sevin)	          low	      no
		malathion	          low	      no
		acephate (Orthene)        moderate    no
________________________________________________________________________________________		

Velvetbean	carbaryl (Sevin)	  low	      no	See above. Asana XL is
 caterpillar	esfenvalerate (Asana XL)  low	      no	toxic to fish and aquatic
		acephate (Orthene)	  moderate    no	invertebrates.
		methomyt (Lannate)	  moderate    no
________________________________________________________________________________________
Wildlife hazards
  high indicates possible wildlife deaths;
  moderate indicates possible wildlife sickness, deaths less likely;
  low indicates sickness unlikely.

Kills
  yes indicates wildlife deaths due to use of the insecticide (active
      ingredient) have been reported.
  no indicates wildlife deaths have not been reported when pesticide
      is used according to label.

Disease Control

Fungicides

Fungicides currently used for disease control in peanuts are only slightly toxic to birds and mammals in field applications. However, some fungicides, such as benomyl (Benlate) and chlorothalonil (Bravo), are extremely toxic to fish.

Benlate can reduce earthworm populations, which could indirectly affect some bird and mammal populations. Thiophanate-methyl (Topsin) may also reduce beneficial soil organisms.

The following recommendations may help to reduce the potential for disease in peanuts. Thus, the need for fungicides and the number of applications required per season can be reduced by:

Fungicides used to control southern stem rot are not highly toxic. Often, however, they are applied with insecticides that range from moderately to extremely toxic to wildlife (see Table 3). If an insecticide must be included, use Lorsban since it is less toxic and requires a lower application rate. Fields with no history of disease should not be treated until symptoms are observed. Where southern stem rot is a problem, consider using a longer rotation to reduce future problems.

Nematicides

Some nematicides are highly toxic to wildlife and have caused wildlife deaths. Specific crop rotations can help control nematodes. Nematicides should be used only when economic thresholds are exceeded. Often, spot treatments are adequate. If a nematicide treatment is necessary, select the least toxic alternative (see Table 4). Also, as with insecticide granules, full incorporation of nematicide granules, including spills, will significantly reduce harm to birds.

Herbicides

Most herbicides used on peanuts are only slightly toxic to birds and mammals. The one exception is paraquat (Gramoxone or Starfire), which is moderately toxic to birds. When paraquat is sprayed directly on bird eggs it can cause abnormal growth of embryos and has been shown to reduce the hatching success of waterfowl eggs. Herbicides usually do not cause direct effects such as these. More often, herbicides affect wildlife indirectly by reducing their habitat.

When habitats are reduced on a farm, there is a tremendous effect on the wildlife populations there. Wildlife need food and cover to survive. Wildlife populations decline when herbicides or mechanical methods are used to maintain "clean" fencerows, ditch banks, and field borders. These strip habitats provide wildlife valuable cover for nesting, brood rearing, and escaping from predators. Many species of wildlife, including quail and rabbits, benefit from strip habitats. Where possible, consider maintaining these areas in wildlife cover. Protect these areas from herbicides and mow less frequently. Consider mowing filter strips and ditch banks and other noncrop areas only once per year in early spring. Another approach is to mow alternate sides of strip habitats every other year. This provides year-round cover for wildlife.

Table 3. Hazard of Nematicides to Wildlife
______________________________________________________________________________

	                     Wildlife
Chemical (Brand Name)	      hazard	Kills      Comments
_______________________________________________________________________________
metam sodium (Vapam)	      low	no	No reports of wildlife problems
				                associated with use.
_______________________________________________________________________________

1-3 dichloro-propene 	      low	no	See above.
     (Telone II)
_______________________________________________________________________________
1-3 dichloro-propene + 	      low	no	See above.
methyl isothiocyanate (Vodex)
_______________________________________________________________________________
1-3 dichloro-propene + 	      low	no	See above.
choropicrin (Telone Cl7)
_______________________________________________________________________________
aldicarb 15G (Temik)	     high	yes	Temik granules exposed on soil
				                surface are a hazard. Fully
				                incorporating granules reduces
				                hazard. Disk in spilled granules
				                at row ends.
________________________________________________________________________________

fenamiphos 15G or            high       yes     Nemacur is very toxic to wildlife.
   3EC (Nemacur)                                Exposed granules are a hazard.
                                                Full incorporation reduces
                                                hazard. Granules spilled at row
                                                ends should be incorporated.
________________________________________________________________________________
Wildlife hazards
  high indicates possible wildlife deaths;
  moderate indicates possible wildlife sickness, deaths less likely;
  low indicates sickness unlikely.

Kills
  yes indicates wildlife deaths due to use of the insecticide (active
      ingredient) have been reported.
  no indicates wildlife deaths have not been reported when pesticide
      is used according to label.






Table 4. Hazard of Southern Stem Rot Treatments to Wildlife
_______________________________________________________________________
                             Wildlife
Treatment (Brand Name)        hazard    Kills    Comments
_______________________________________________________________________
PCNB (Terraclor)               low        no     PCNB is only slightly
                                                 toxic to birds and 
                                                 mammals.
_______________________________________________________________________
carboxin (Vitavax)             low        no     Slight oral toxicity to
                                                 wildlife.
_______________________________________________________________________
PCNB + chlorpyrifos            moderate   no     Granules exposed on soil
       (Lorsban)                                 surface are a hazard to
                                                 birds. Disk under spilled
                                                 granules at row ends.
________________________________________________________________________
chlorpyrifos (Lorsban)         moderate   no     See above.
________________________________________________________________________
PCNB + fonofos (Dyfonate)      high       no     Fonofos is highly toxic
                                                 to birds. Granules exposed
                                                 on soil are a hazard.
                                                 Incorporate spilled
                                                 granules.
________________________________________________________________________
PCNB + ethoprop (Mocap)        high       yes    Ethoprop is highly toxic
                                                 to birds. Granules exposed
                                                 on soil surface are a
                                                 hazard.
________________________________________________________________________
Wildlife hazards
  high indicates possible wildlife deaths;
  moderate indicates possible wildlife sickness, deaths less likely;
  low indicates sickness unlikely.

Kills
  yes indicates wildlife deaths due to use of the insecticide (active
      ingredient) have been reported.
  no indicates wildlife deaths have not been reported when pesticide
      is used according to label.

For further information on this topic, contact your county Extension Service agent.

see also: