Introduction

636
Field Scouting in Clovers
Defoliators
• Sweetclover Weevil
º Typical Damage: Adults chew crescent-shaped and jagged notches in leaves and can completely defoliate plants.
º When and How to Monitor: Inspect clover seedlings for weevil damage in spring as the seedlings emerge. In
midsummer and throughout August, inspect first-year clover stands for damage along crop margins. Invading
weevils move into these stands only as far as necessary to satisfy their food requirements, so an insecticide
application to affected field margins is usually all that is required. Visually estimating the number of weevils per
plant must be done carefully because weevils fall from plants easily and are difficult to see on the ground.
º Economic Threshold: 1 st year stands: 1 weevil adult/3 seedlings (1/5 seedlings under dry conditions). 2 nd year
stands: 9-12 weevil adults/plant.
Clovers (sweet, red, alsike) Insect Management Chart
Insect
Grasshoppers
Sweetclover
Weevil
Alfalfa weevil
Lesser clover
leaf weevil
Insecticide
(and insecticide group 1 )
Rate/Acre
Preharvest
interval (days)
Application
(A=aerial;
G=ground)
LD 50
(Mammalian
Toxicity) 2
Defoliators
Spreadable Bran Baits
Eco bran (C) 0.8-1.6kg 2 G N/A
Sprays
Malathion 85E (OP) 0.445-0.544 L 7 A or G 5,500
Lagon (OP) 172-405 ml 2-28 (see label) A or G 425
Locate new seedlings as far as possible from 2nd-year clover. Cultivating second-year stands of sweet clover
silage and hay as soon as possible after the crop is taken kills the new- generation weevil larvae in the soil.
Malathion 500 (OP)
(sweet clover only)
Malathion 85E (OP)
(sweet clover only)
Lagon /Cygon 480 EC /
Cygon 480-AG (OP)
Coragen (D)
(suppression only)
Decis 5 EC /Poleci (P)
(suppression only/
red clover seed
production only)
0.56-1.01 L
0.445-0.544 L
7-Cattle may
be returned
immediately after
spraying.
A or G 4302
5,500
0.34-0.45 L 28 A or G 60-450
152-202 ml 0 G >5,000
101 ml (Decis)
202 ml (Poleci)
Sap or Fluid Feeders
G 395
Lygus Bugs Dibrom (OP) 0.42-0.85 L 4 A or G 345
Leafhoppers Malathion 85E (OP) 0.445-0.544 L 7 A or G 5,500
Dibrom (OP) 0.42-0.85 L 4 A or G 345
Aphids Malathion 85E (OP) 0.445-0.544 L 7 A or G 5,500
Dibrom (OP) 0.42-0.85 L 4 A or G 345
ALWAYS CONSULT THE INSECTICIDE LABEL BEFORE APPLYING ANY INSECTICIDE.
1
Insecticide Group: D=diamides, P=pyrethroids, C=carbamates, OP=organophosphates.
2
LD 50
values represent the relative toxicity of a pesticide. They represent the dose (in mg/kg body weight) that will kill 50% of the
test animals. Thus the lower the number the greater the toxicity. Values given are for oral LD 50
.