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Insect Management in Sorghum 1
Richard K. Sprenkel 2Sorghum is grown over a wide geographical range in Florida and is being planted from early spring until mid-summer. There are several insect pests that reduce yields and hamper growth of sorghum. The grower should be aware of all available control measures for certain expected insects if sorghum is to be grown. Although numerous insects will be encountered, the major problems are likely to be from the pests described in this program (Table 1 ).
Description of Insect Pests
Aphids
These soft-bodied insects are often called "plant lice". These pests are small in size, ranging from 1/16-1/8 inch in length. They damage young sorghum plants and cause problems with the emerging seed heads. The aphids and greenbugs cause damage by sucking the juice or sap from the plant and further complicate harvest since they give off body wastes in the form of honey dew. This syrupy fluid often causes the grain heads to become sticky and makes it difficult to combine the crop. A black fungus known as sooty mold also will grow on the honey dew contaminated seed heads and gives them a dark-colored appearance.Armyworms
Various armyworms occur in Florida and can cause severe damage to sorghum by feeding on the seed head. The stripes and coloration of these worms are highly variable. The most prevalent armyworm is likely to be the fall armyworm. The worm reaches a maximum size of about 1 1/2 inches long and is predominately greenish or greyish-brown in color. The head capsule is generally dark brown to almost black in color and is quite shiny in appearance. The front (head-on view) of the head capsule has a whitish-yellow colored inverted Y which is easily seen by the unaided eye.The fall armyworm feeds on sorghum when the crop is in the whorl stage (as a budworm). It also feeds on the leaves and developing seed heads. This pest can begin its attack in the spring months and usually reaches two population peaks, one in late July and a second in late August.
The female moth lays eggs in batches of 100-150 eggs. The eggs are covered with a cream to tan colored "felt-appearing" material (body hairs). The egg masses are generally located on the undersurface of the leaves. The eggs hatch in 3-7 days, and the tiny black-colored larvae appear in tremendous numbers "all-at-once". The larval stage lasts for about 14 days depending on the temperature. The larvae then drop to the soil and pupate for about 7-10 days and then emerge as an adult. The entire life cycle takes approximately 30 days.
Chinch Bugs
At times this pest may attack sorghum in Florida. The adult chinch bug is approximately 1/8 inch long and is characterized by a black body with silver-colored wings. The immature chinch bugs are somewhat smaller and are reddish in color with a single white band running across their back. Both nymphs and adults suck plant juices and cause the leaves of the plants to appear red. When plants are less than 18 inches high, severe feeding can cause wilting and stunting. Chinch bugs cause more damage in hot dry weather.
Figure 1. Several stages of teh chinch bug on a sorghum leaf. If insecticides are to be used, the grower is encouraged to use ground spray equipment and direct the nozzles at the infested portions of the plants. In most cases the bugs are located on the lower parts of the main plant stem and on the lower leaves.
False chinch bugs are similar to chinch bugs in appearance and habits. The false chinch bugs are usually found feeding on the heads of the sorghum plant. These pests can cause a reduction in seed quality and quantity by sucking the juices from the developing seeds and plants.
Corn Earworms
This insect is a general feeder on corn, cotton, tomatoes, soybeans, peanuts and numerous other crops as well as sorghum. These caterpillars are found in many colors such as pink, yellow, green, brown, and almost black. Like the armyworms, the corn earworm will curl up into a ball when disturbed. The female moth lays tiny eggs, one at a time, over the plant. The eggs hatch in 2-7 days, and the tiny larvae are almost black in color. These worms resemble the fall armyworm in size and appearance and reach about 1 1/2 inches in length before pupating.
Figure 2. Corn earworm on sorghum head. The larvae differ somewhat in appearance from the fall armyworm in that their head capsule is generally yellowish to orangish in color, and the obvious inverted 'Y' found on the head capsule of the fall armyworm is absent on the corn earworm.
The corn earworm will also feed in the whorls of sorghum but prefers the seed heads. After feeding as larvae for about 14 days, the caterpillars drop to the soil and pupate for a period of approximately 7-10 days. The entire life cycle takes approximately 30 days to complete. There are several generations per year with peaks usually occurring in late July and again in late August.
Late planted sorghum is frequently damaged heavily by corn earworms and the pest seems to be attracted to the compact seed head varieties.
Cutworms
These night-feeding worms often cause problems when the sorghum is grown during periods of cool nights and warm days. The most dangerous conditions are when sorghum is planted behind a grass or weed crop that is harboring large populations of overwintering larvae. If the larvae are not reduced by proper and thorough cultivation or killing the vegetation several weeks before planting, they often will reduce a sorghum stand so that replanting may be necessary. The cutworms can reach 1 1/2-2 inches in length when full grown and will often cut or "graze down" seedling sorghum.If baits are to be used, they should be applied in the late afternoon or early evening hours in order to produce the best results. If sprays are to be used, ground application units with nozzles set to direct the spray at the base of the plants give good results.
Lesser Cornstalk Borers
This pest has become extremely difficult to control on both young and old sorghum plantings and, in particular, on those following rye and other grass crops.The female moth lays eggs on or around the sorghum plant. Upon hatching, the young larvae will feed for a short period of time on the above-ground plant parts before migrating to the below-ground parts. The larvae will usually bore into the underground tap root approximately 3/8 inch below the soil surface.
The worm will construct a dirty, white, fragile, silk-like tube that will be found dangling from the root. The tube will be approximately 1/2-1 inch long and because of its sticky nature will have sand particles covering it.
The larvae will reach about 5/8-3/4 of an inch in length when full grown and it will usually take about 2 weeks for it to progress through this stage. The pupal stage occurs in the soil and the entire life cycle of the pest can be completed in approximately 21-30 days.
The larvae are quite easy to identify since they have alternating aqua-blue and wine-colored bands encircling their body. The head capsule is small and shiny black. The worm will wiggle "violently" when disturbed. This pest prefers dry, hot weather and sandy soils. It is an extremely severe pest on late planted sorghum.
Mites
Mites are small non-insect pests that can feed on sorghum leaves, causing considerable damage. The mites are only 1/60-1/50 of an inch long and resemble miniature spiders and generally are pale green in color. Spider mites spin webs which can cover leaves and heads during periods of heavy infestation.Mites usually establish themselves on the under-side of lower plant leaves and migrate upwards to the head as populations and damage increase. Periods of hot, dry weather favor population build-ups. Sorghum will tolerate mites better if it is not undergoing water stress. Research indicates that yields are not hurt if mite attacks occur at or after the hard dough stage.
Mites are able to complete their life cycle in short periods of time, going from the egg to the adult stage within 7-10 days or less. Their feeding causes the sorghum to become off-color and to take on a "dusty" appearance.
Sorghum Midge
The adult midge is a delicate orange colored "gnat-like" fly about 1/12 of an inch long.
Figure 3. Adult midges emerge from their pupal stage shortly after daybreak and mate soon afterwards. The individual female may deposit from 30 to as many as 200 tiny white eggs. The female may also lay from 8 to10 eggs in an individual grain kernel.
Figure 4. Sorghum midge ovipositing into sorghum flower. A single larva is capable of destroying the contents of a developing seed. Females seldom live more than a day while males live only a few hours. Egg-laying generally occurs from 8:00 to 10:00 AM and approximately one hour before sunset.
Eggs hatch in approximately 2 days. The stout-looking, orangish-red maggots (larvae) begin feeding on the developing seed and will require from 9-11 days to complete the larval stages. The pupal stage will last for approximately 3 days, whereupon they emerge as adults. The life cycle is complete within approximately 15-24 days depending on weather conditions. The midge can tolerate very cold temperatures and overwinters as larvae wrapped in cocoons within the spikelets of host plants and emerge as adults in the spring. They usually infest Johnsongrass and other wild hosts until sorghum starts to bloom.
Early sorghum midge infestations do not usually cause enough damage to economically merit control. However, early generations contribute to an overall population build-up and the pest generally reaches higher numbers as the warm weather continues. Sorghum blooming in mid-to-late summer generally is infested with the midge.
Midge damage appears as blasted or blighted seed heads. The damage often resembles heads that are diseased, that have been hit by hard rains, or that are suffering from a lack of fertilizer.
Sorghum Webworms
The webworms are hairy caterpillars and grow to a maximum length of approximately 1/2 inch long. They are greenish to yellowish in color with well-marked darker stripes running lengthwise down their body.
Figure 5. Sorghum webworm larva no sorghum head. They hibernate in plant debris above ground and emerge as soon as weather permits in the spring. There can be and usually are several generations a year in Florida. The webworms feed almost entirely on the developing seeds and the larvae can often completely destroy the grain seed in the head. The larvae will spin a web during feeding; however, the webs are often very inconspicuous (to the observer). The eggs hatch in approximately 5 days and the larva takes an additional estimated 15 days to reach full size. The pupal stage lasts approximately 7-10 days. It takes approximately 30 days for the entire life cycle to be completed.
The adult webworm moth is nearly white in color with irregular dark markings along the rear margin of the forewings (front pair of wings). With wings fully expanded, the moth measures about 1/2 inch across. During some years the sorghum webworm has caused extensive damage, though in most cases damage is usually localized in late season plantings. Webworms are favored by cool wet weather during late summer and early fall. Generally the caterpillars do most of their feeding while the grain is in the milk to soft dough stage. Webworms seem to prefer the compact seed head varieties.The pests partially hollow out and consume many individual seeds in a head. Small white fecal droppings may indicate fairly heavy infestations. These droppings also increase the likelihood of secondary molds and fungi which can add to the overall poor quality of the seed.
Stink Bugs
Green stink bugs, brown stink bugs and several other species are capable of causing damage to grain sorghum.
Figure 6. Southern green stink bug feeding on sorghum grain.
Figure 7. Brown stink bug feeding on sorghum grain. Scouting Techniques
Sorghum, like other row crops, needs to be scouted for insects on a regular basis during the growing season. Sampling varies somewhat depending on the stage of the crop. However, regardless of the crop stage, all samples should be selected at random and should be representative of the fields scouted. In general, approximately 20% of the samples should be taken from the edge of the field and the remainder taken from the interior of the field.Before heading, monitor grain sorghum once every 7 days. For each 2 acres of field size, sample 1 site consisting of 5 consecutive plants. Examine each plant giving particular attention to both leaf surfaces of the uppermost leaves. Count the number of plants having fall armyworm egg masses and/or newly-hatched fall armyworm larvae. Also count the number of plants having live fall armyworms or corn earworms in the whorls. Always examine at least 20 sites (100 plants) regardless of field size. In fields larger than 50 acres, sample one site (five plants) for each 3 acres of field size. For example, in a 75 acre field, check 25 sites (125 plants). After scouting a field, determine and record the percentage of plants infested with fall armyworm eggs or newly-hatched larvae (number of plants having eggs or newly-hatched larvae divided by the total number of plants examined x 100%). Also determine and record the percentage of plants infested with live corn earworms or fall armyworms in the whorl (number of plants with worms in the whorls divided by the total number of plants examined x 100%).
From late boot to 40% bloom, sample grain sorghum 2 times per week. From 40% bloom until 90% of the heads are in the early milk stage, check sorghum three times per week. Examine 5 heads per 2 acres and always sample at least 50 heads per field. Do not examine heads of consecutive plants. Because the sorghum midge is easily disturbed, always walk several paces between sampled heads. Always take samples for sorghum midge before 10:00 AM since they are most active early in the morning. To sample the grain heads for midges, webworms, fall armyworms, and corn earworms, you will need a plastic bag that is approximately 6 x 3 x 15 inches. Without disturbing the plant, quickly slip the bag over the head, clamping the bag shut beneath the head. Shake the head vigorously in the bag for 2 to 3 seconds. Without opening the bag, examine the plastic bag for adult sorghum midges which will fly toward the sun when disturbed. Next, remove the head from the bag by tipping the upper part of the sorghum plant downwards. Pour the contents of the bag into your hand and count the sorghum webworms, fall armyworms, and corn earworms. After sampling five plants, record the total number of each of the major pests of grain sorghum found. Worm size should be noted. When the samples for the field have been taken, determine the average number of sorghum midges, sorghum webworms, fall armyworms, and corn earworms per head.
From late milk stage until the crop is mature, sample sorghum heads once every 7 days for sorghum webworms, fall armyworms, and corn earworms using a plastic bag in the manner previously described above.
Lesser cornstalk borer should be sampled from crop emergence until plants are 12 inches tall. Samples should be made to include the borders as well as the interior portions of the field. At least 10 inspection sites should be made for the average size field with 2 (20 percent) of the samples being made from the borders and 8 (80 percent) being made from the interior part of the field. A single sample should consist of observing at least 10 row feet of plants in succession and observing to see if any of the young plants were: (1) wilted, (2) off-color, (3) stunted, or (4) dying. If any plants are observed in the aforementioned state, then they should be carefully troweled, "spooned," or dug up. The excess soil should gently be shaken from the roots and observations made to determine if the 3/4-1 inch long dirty silken-like tube(s) are found attached to the plant root. The observation of this "tell-tale" tube alerts the grower to the presence of the pest. The tube is attached at the point of entry of the borer into the plant and generally is found approximately 1/4-3/8 inch below the soil surface.
Action Thresholds For Sorghum Insect Pests
The sorghum midge is a sporadic pest of sorghum. However, it can cause considerable losses over a relatively short period of time if left unchecked. Chemical control for this pest is usually justified when there is an average of one adult midge per two heads (0.5 midge per head). The action threshold for the sorghum webworm is 3-5 larvae per head.Thresholds for the fall armyworm and corn earworm vary depending on whether the sorghum plant is in the whorl stage or has headed out. Before heading, the action threshold is when 5% of the plants have fall armyworm egg masses or newly-hatched larvae present. Treatment may also be justified if 50% of the plants have live fall armyworms or corn earworms in the whorl. However, control of worms in the whorl is extremely difficult. Best results have been obtained when a recommended insecticide is applied in 25 or more gallons of water per acre at low pressure through a nozzle directed into the whorl.
After heading, when the fall armyworm and corn earworm feed on the grain, an average of 1-2 worms per head usually justifies treatment. If sorghum webworm, fall armyworm, and corn earworm are all present in a field, thresholds must be adjusted downward accordingly. For example, a field having an average of two sorghum webworms plus one fall armyworm and/or corn earworm per head usually justifies treatment.
Phytotoxicity and Pesticide Restrictions
The use of organo-phosphatic insecticides can be phytotoxic to certain varieties of sorghum. Sweet sorghum is particularly sensitive. Read the label carefully for all warnings and precautions.The use of trade names in this publication is solely for the purpose of providing specific information. It is not a guarantee or warranty of the products named and does not signify that they are approved to the exclusion of others of suitable composition.
Insecticide restrictions for sorghum in Florida:
Comite: Do not make more than one application/year.
Counter: Maximum of one application/year. Maximum of 8.4 lb/a.
Dimethoate: Do not make more than 3 applications/season.
Lannate: Do not apply more than 0.9 lb ai/a/crop. Do not make more than 2 applications/crop. Do not use on sweet sorghum.
Lorsban: Do not exceed 3 pt/season. Do not treat sweet sorghum.
Lorsban 15G: Do not make more than one application/season.
Mustang Max: Extremely toxic to fish and bees. Do not make applications less than 14 days apart. Do not apply more than 0.125 lb ai/a.
Sevin 80 S: Do not apply more than 7 1/2 lb/a/crop. Do not make more than 4 applications/season. Do not reapply within 7 days.
Sevin XLR: do not apply more than 6 qt/a/crop. Do not make more than 4 applications/season. Do not reapply within 7 days.
Temik: Do not feed green forage to livestock. Do not make more than one application/year. Do not exceed a total of 7 lb/a.
Thimet: Do not exceed 6.5 lb/a, do not apply more than once/season, do not allow to contact seed.
Tracer: Do not apply more than 14.4 oz/a/year or 0.45 lb ai/a/season.
Warrior Z: Do not exceed a total of 0.08 oz/a/crop/season or 0.06 oz/a after emergence or 0.02 oz/a after soft dough stage.
Additional Information
Crop Data Management Systems (Label Search) http://www.cdms.net/manuf/manuf.asp .Sorghum Insect Pests. http://www.isis.vt.edu/~fanjun/text/Link_pest18.html.
Table 1. Insecticides for use on sorghum in Florida
Trade Name (Common Name)
lb ai/a
Formulation/a
Acres/gal or lb
Min Days to Harvest and Restrictions
APHIDS
Counter 20 CR (terbufos)
50-grazing; 100-fodder, grain Apply at planting.
Dimethoate 4 EC (dimethoate)
0.25-0.5
0.5-1 pt
16-8
28-feed or grazing.
Lorsban 4E (chlorpyrifos)
0.25-0.5
0.5-1 pt
16-8
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
ARMYWORMS (See also: Fall Armyworms)
Lannate 2.4 LV (methomyl)
0.23-0.45
0.75-1.5 pt
10.67-5.3
14
Lorsban 4E (chlorpyrifos)
0.5-1
1-2 pt
8-4
30-up to 1 pt rate; 60-more than 1 pt rate
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain, fodder; 14-forage, grazing
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Tracer (spinosad)
0.047-0.094
1.5-3 oz
85-43
7-grain, fodder; 14-forage.
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
BEET ARMYWORMS
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
Lannate 2.4 LV (methomyl)
0.23-0.45
0.75-1.5 pt
10.67-5.3
14
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
CHINCH BUGS
Counter 20 CR (terbufos)
Apply at planting. 50-grazing; 100-fodder, grain
Lorsban 15G (chlorpyrifos)
Apply at planting (suppression)
Lorsban 4E (chlorpyrifos)
0.5-1
1-2 pt
8-4
30-up to 1 pt rate; 60-more than 1 pt rate
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Temik 15G (aldicarb)
max 1.05
7 1/2 oz/1000 ft row
Warrior Z (cyhalothrin)
0.03
3.84 oz
33.3
30-grain
CORN EARWORMS
Lannate 2.4 LV (methomyl)
0.23-0.45
0.75-1.5 pt
10.67-5.33
14
Lorsban 4E (chlorpyrifos)
0.5-1
1-2 pt
8-4
30-up to 1 pt rate; 60-more than 1 pt rate
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Tracer (spinosad)
0.047-0.094
1.5-3
85-43
7-grain or fodder; 14-forage
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
CORN ROOTWORMS
Counter 20 CR (terbufos)
100-grain fodder; 50-graze, forage. Apply at planting.
Lorsban 15G (chlorpyrifos)
Apply at planting.
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
CUTWORMS
Lorsban 4E (chlorpyrifos)
0.5-1
1-2 pt
8-4
60-forage, fodder, hay, or silage.
Lorsban 15G (chlorpyrifos)
Apply at planting.
Mustang Max (zeta-cypermethrin)
0.008-0.025
1.28-4 oz
100-40
14, 45-stover
Sevin 80S (carbaryl)
1
2.5 lb
0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1
2 qt
2
21-grain; 14-forage
Warrior Z (cyhalothrin)
0.015-0.02
1.92-2.56 oz
66.7-50
30-grain
EUROPEAN CORN BORERS
Lorsban 4E (chlorpyrifos)
0.75-1
1.5-2 pt
5.3-4
60-forage, fodder, hay, or silage.
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
FALL ARMYWORMS (See also: Armyworms)
Lannate 2.4 LV (methomyl)
0.23-0.45
0.75-1.5 pt
10.7-5.3
14
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
FLEA BEETLES
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Warrior Z (cyhalothrin)
0.025-0.03
2.56-3.84 oz
50-33.3
30-grain
GRASSHOPPERS
Dimethoate 4 EC (dimethoate)
0.5
1 pt
8
28-grazing, feed
Lorsban 4E (chlorpyrifos)
0.25-0.5
1/2-1 pt
16-8
30
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
GREENBUGS
Counter 20 CR (terbufos)
50-grazing; 100-grain, fodder Apply at planting
Lorsban 4 E (chlorpyrifos)
0.25-1
1/2-2 pt
16-4
30-up to 1 pt rate; 60-more than 1 pt rate
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
Temik 15 G (aldicarb)
max 1.05
7 1/2 oz/1000 ft row
Thimet 20 G (phorate)
6 oz/1000 ft row
30 Do not feed foliage before grain harvest
LESSER CORNSTALK BORERS
Lorsban 4E (chlorpyrifos)
0.5-1
1-2 pt
8-4
30-up to 1 pt rate; 60-more than 1 pt rate
Lorsban 15 G (chlorpyrifos)
Apply at planting.
Mustang Max (zeta-cypermethrin)
0.02-0.025
3.2-4 oz
45-40
14, 45-stover
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
MITES
Comite II 6 E (propargite)
1.1-1.7
1 1/2 -2 1/4 pt
5.3-3.6
30-silage; 60-grain. (For two spotted mite and Banks grass mite.
Dimethoate 4 EC (dimethoate)
0.5
1 pt
8
28 (Banks grass mite, spider mite)
Microthiol Disperss (sulfur)
6.4-8
8-10 lb
0.1-0.125
Repeat as necessary
SORGHUM MIDGE
Dimethoate 4 EC (dimethoate)
0.125-0.25
1/4-1/2 pt
32-16
28-feed, grazing
Lannate 2.4 LV (methomyl)
0.25-0.45
3/4-1 1/2 pt
10.7-5.3
14
Lorsban 4 E (chlorpyrifos)
0.25
1/2 pt
16
30-forage, fodder, hay, or silage
Mustang Max (zeta-cypermethrin)
0.008-0.025
1.28-4 oz
100-40
14, 45-stover
Warrior Z (cyhalothrin)
0.015-0.02
1.92-2.56 oz
66.7-50
30-grain
SORGHUM WEBWORMS
Lannate 2.4 LV (methomyl)
0.45
1 1/2 pt
5.3
14
Lorsban 4 E (chlorpyrifos)
0.5
1pt
8
30
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Tracer (spinosad)
0.047-0.094
1.5-3
85-43
7-grain or fodder; 14-forage
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
SOUTHERN CORN ROOTWORMS
Counter 20 CR (terbufos)
50-grazing; 100-fodder, grain Apply at planting.
Lorsban 15G (chlorpyrifos)
Apply at planting.
STINK BUGS
Mustang Max (zeta-cypermethrin)
0.011-0.025
1.76-4 oz
73-40
14, 45-stover
Sevin 80S (carbaryl)
1-2
1.25-2.5 lb
0.8-0.4
21-grain; 14-forage
Sevin XLR (carbaryl)
1-2
1-2 qt
4-2
21-grain; 14-forage
Warrior Z (cyhalothrin)
0.02-0.03
2.56-3.84 oz
50-33.3
30-grain
WHITE GRUBS
Counter 20 CR (terbufos)
50-grazing; 100-grain, fodder Apply at planting.
WIREWORMS
Counter 20 CR (terbufos)
50-grazing; 100-grain, fodder Apply at planting.
Footnotes
1. This document is ENY-404 (IG063), one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date: January 1, 1993. Revised: December 2005. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.2. Richard K. Sprenkel, professor, Department of Entomology, North Florida Research and Education Center--Quincy; Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611
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