E-209
DEPARTMENT OF ENTOMOLOGY
field crops insects

RELATIONSHIP OF TILLAGE SYSTEMS TO INVERTEBRATE AND VERTEBRATE PEST ACTIVITY
C. Richard Edwards and Marlin K. Bergman, Extension Entomologists, and F. Thomas Turpin, Research Entomologist

Weather conditions and certain cultural practices to a large degree, govern when invertebrates (insects, slugs, etc.) and vertebrates (birds, rodents, etc.) may be present in a field crop and if they are likely to become "economic" (i.e., loss may occur if some form of control is not utilized). The major cultural factors affecting pest presence and activity are: crop rotation, date of planting, and type and degree of crop residue, which is determined largely by the tillage program used.

The following tables show the potential effects of four common tillage systems on the presence and abundance of selected invertebrate and vertebrate pests. Table 1 deals with those in soybeans, and Table 2 with those in corn. The tables indicate that, normally, one can expect somewhat greater activity by
some pests in no-till than in conventional or reduced-tillage systems.

Chemical control measures are not presented here since chemical and pest situations change yearly.	However, it should be noted that, generally, planting-time applications of an insecticide in no-till and some reduced-tillage systems may not provide as effective control of certain pests as an application in a conventional system. For example, a particular insecticide would likely give better corn rootworm control as a band application under conventional tillage than as an infurrow application under some conservation tillage system.
Additional information on the various pests listed in the tables and suggested chemicals for their control can be obtained at your local county Cooperative Extension Service Office.

Table 1. EFFECTS OF TILLAGE SYSTEMS ON SOYBEAN INVERTEBRATE AND VERTEBRATE PEST ACTIVITY. 1, 2
Pest	Fall plow	Spring plow	Chisel or disc	No-till	Effective control
Mexican bean beetle	0	0	0/-	-/0	Rescue insecticide
Grasshoppers	-	-	0/-	+/0	Rescue insecticide
Green cloverworm	0	0	0	0	Rescue insecticide
Potato leafhopper	0	0	0/+	0/+	Rescue insecticide
Japanese beetle	0	0	0	0	Rescue insecticide
White grubs	0/-	0/-	0/+ (sod)	+ (sod)	None
Wireworms	0/-	0	0/+ (sod)	+ (sod)	None
Seedcorn maggot 3	0/-	0/-	0/+	+ (residue)	Seed treatment
Rodents	-	-	0/-	0/+ (cover)	Seed treatment, baits
Deer	0	0	0	0	None
* Footnoted items explained in footnotes following Table 2.

COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA 47907