Introduction

656
Defoliators
• Grasshoppers
º Typical Damage: Black strips along margins of newly emerging crops, head clipping later in season.
º When and How to Monitor: Look for grasshoppers when monitoring fields from late – May through to harvest.
Check along edges of crop, particularly areas adjacent to hayland, pastures and roadsides. Estimate number of
hoppers/yard 2 (m 2 ).
º Economic Threshold: 8-13 grasshoppers/m 2 . Early in the season, when grasshoppers are small, 18 grasshoppers/m 2
and visible crop damage may be a more appropriate threshold.
º A rough estimate for an economic threshold for grasshoppers in crops to be used as greenfeed has been
suggested at 20 grasshoppers/m 2 or higher.
• Armyworms
º Typical Damage: Leaves stripped from plants, awns chewed from heads, heads clipped.
º When and How to Monitor: Check the soil surface for armyworms, and the plants for feeding, when monitoring in
mid- June through early-August. At each stop shake plants and carefully check soil surface for dislodged larvae.
During the day larvae may be under plant trash, soil clods or in soil cracks. Check the backs of armyworms for
parasite eggs.
º Economic Threshold: Four unparasitized larvae, smaller than 2.5 cm (1 inch) per square foot. If heads are being
clipped, treat when two or more armyworms per square foot are present. For migrating Armyworms: Treat a couple
of swaths ahead of the infestation in the direction of movement to form a barrier strip.
Seed Feeders Only
• Wheat Midge (wheat only)
º When and How to Monitor: Monitor wheat in July when crop emerges from boot stage until flowering. Check crop
canopy at dusk for signs of wheat midge adult activity. At each stop, examine 10 heads. Record the number of
midge adults observed on or near heads. Calculate average number of midge per head.
º Sticky traps may be used to capture adult midge activity in wheat fields.
º Economic Threshold: For yield only: 1 adult midge per 4 to 5 heads. At this level of infestation, wheat yields will
be reduced by approximately 15% if the midge is not controlled. To maintain optimum grade: 1 adult midge per
8 to 10 wheat heads during the susceptible stage.
Small Grain Cereals (wheat, barley, oats) Insect Management Chart
Insect
Insecticide
(and insecticide group 1 )
Rate/Acre
Preharvest
interval (days)
Application
(A=aerial;
G=ground)
LD 50
(Mammalian
Toxicity) 2
Belowground and Surface Feeders
Wireworms Cruiser Vibrance Quattro (N) 325 ml/100 kg seed Seed Treatment >5,000
Cruiser 5FS (N)
(Wheat and barley only)
17-50 ml/100 kg seed May be applied on-farm or by commercial seed treaters.
Nipsit Suite Cereals (N)
(Wheat only)
Nipsit Inside (N)
Alias 240 SC (N)
326 ml
per 100 kg seed
17-100 ml
per 100 kg seed
42-125 ml/
100 kg seed
Seed Treatment Seed Treatment >5,000
Seed Treatment Seed Treatment 3,044
Seed Treatment
Sombrero 600 FS 17-50 ml/100 kg seed Seed Treatment Seed Treatment
Raxil ProShield (N) A co-pack of Raxil Pro and StressShield 600
Raxil WW (N)
A combination of Raxil MD and Stress Shield (imidacloprid).
Cutworms Coragen (D) 101 ml 1 A or G >5,000
Decis 5EC /Poleci (P) 80 ml (Decis)
162 ml (Poleci)
31 (oats)
40 (barley, wheat)
A or G 395