APHIDS
(Homoptera: Aphididae)
I. BIOLOGY AND ECOLOGY
Aphids are small (1-3 mm long), soft-bodied, pear-shaped insects that suck plant juices. Aphids are sometimes called green-files, black-files or plant lice. Winged or wingless, they vary in color and shape. Most aphids are green, yellow or pink in color. Those found in field crops may be one of these colors or white, bronze, dark-brown or black. Sometimes the wingless form is green where as the winged form of the same species Is black. The antennae are usually quite long.
Aphids can be distinguished from similar insects by examining their 'tall' ends. Aphids bear a pair of tubes at the tips of their abdomens that resemble tiny exhaust pipes. These tubes are called 'cornicles'. Also, aphids tend to move very slowly compared to insects that are similar in appearance.
1. Species Described:
Corn leaf aphid, Rhaphalosiphum maidis
A greenish-blue aphid, this species has short, broad comic s with a dark spot surrounding their base. The legs, cornicles, and cauda (a tail-like structure) are black. It is usually about 3 mm long. It is found in colonies on stems and upper leaves of barley and corn, secreting much sticky honeydew.
English grain aphid, Macrosiphum avenae (Sitobion avenue of some authors)
Sometimes this aphid is also called the grain aphid. Bright green with long, black cornicles and antennae, this species has legs that are banded with areas of green and black. The cornicles are long and narrow. It Is found In colonies or scattered on leaves, stems, or in the heads of cereals and cultivated grasses.
Greenbug, Schizaphis graminum
Pale- to bright- green in color, these aphids have a dark stripe down the middle of the back. The antennae are long and black. The adults are up to 2 mm long. The legs and cornicles are pale green with black tips. It is found in colonies on leaves of cereals. When feeding, a toxic saliva is infected in to the plants causing discoloration and brown spotting at feeding sites. These are called necrotic spots.
Oat birdcherry aphid, Rhophalosipharn padi
Sometimes also called the bird cherry oat aphid or the cereal aphid, this species is dull-olive-green, with a reddish-orange patch between and at the base of the cornicles. It is about 2 mm long. The legs and short cornicles are pale-green with black tips. The antennae are black. It is found in colonies or scattered on lower leaves, stems, and roots of cereals and grasses.
Pea aphid, Acyrthosiphon pisum
The pea aphid is common wherever legumes are grown. Adult pea aphids are soft-bodied, slow-moving, and range in color from light to dark green. They are pear shaped, about 3 mm long and 1.5 mm wide, with long slim legs. Nymphs are smaller but closely resemble adults. Adults and nymphs have long slender cornicles.
Potato aphid, Macroslphun euphorbiae
The potato aphid is common is common on potatoes and, to a lesser degree, on flax. Adult potato aphids are large, elongated, and soft-bodied. The body is variable in color - either yellow, green, or pink, with a darker dorsal ridge. They are wedge-shaped. The antennae are about as long as the body. They are the largest of the potato-infesting aphids (MacGillvray,1979).
Russian wheat aphid (RWA), Diuraphis noxia
These aphids are relatively small, lime-green in color, and have an elongated, spindle-shaped body. They lack the typical comicles but have a projection above the caudal or tail segment which gives them a "forked tail' appearance, when viewed from the side.
Wheat, barley and trticale are preferred host plants. Damage symptoms include white, yellow or green longitudinal streaks along the leaves caused by toxins injected into the host while feeding. Other damage includes curled leaves and flattened, discolored plants that will eventually die if the aphids are not controlled.
This species is rapidly becoming a major insect pest of small grains in wheat- and barley-producing regions of the western U.SA and Canada. The RWA spread from Mexico (early 1980's) to Texas (1 986)and north through the Great Plains (1987) into western Canada (1988). It was first discovered In Alberta and Saskatchewan in July, 1988, infesting winter wheat. It has not yet been reported from Manitoba.
Aphids on small grains may be identified using special aphid toxonomic keys (e.g., for the adults, Peairs, 1987; for the immatures, Olsen et al., 1993). However, identifications are best left to aphid taxonomists for several reasons: i.e.,
2. Geographical Distribution:
All of the aphids mentioned above (plus many other less common species) occur in Manitoba.
Being 'sap-suckers', aphids are usually found on the growing tips and undersides of leaves, where they
aggregate in large numbers (Auclair,1963). Some aphids may attack the bases of stems or the roots.
Corn leaf aphids are found in colonies on stems and upper leaves of barley and corn, secreting much sticky honeydew.
English grain aphids are found in colonies or scattered on stems, or in the heads of cereals and cultivated grasses.
Greenbugs are found in colonies on leaves of cereals.
Oat birdcherry aphids are found in colonies or scattered on lower leaves, stems, and roots of cereals and grasses.
Pea aphids are common wherever legumes are grown, especially in the Red River Valley of Manitoba.
Potato aphids, in addition to being found in potato fields, are becoming increasingly common in flax fields in Manitoba.
Russian wheat aphids have not yet been reported from Manitoba.
In Manitoba, aphids can be a problem on small grains. These include wheat [Triticum aestivum], barley[Hordeum murinum], triticale [Triticosecale rimpaui], rye [Secale cereale], and oats [Avena sativa]).
When not feeding on field crops, they may be present on grasses (e.g., brome or rescue grass [Bromus spp.], barnyard grass, canarygrass [Phleum pratense], bluegrass, cheatgrass, goat grass, orchardgrass, squirreltail, timothy, wheatgrass [Elytrigia elongata], and wild oats).
Corn leaf aphids feed on barley and corn in Manitoba. Occasionally, it is found on voluntary wheat and oats.
English grain aphids feed on cereals (including wheat, barley, rye, and oats) and on cultivated grasses.
Greenbugs feed on cereals. They prefer wheat, oats, barley and rye, especially if sown late.
Oat birdcherry aphids feed on cereals and grasses.
Field peas, alfalfa and clovers are the main hosts of the pea aphid. In Manitoba, it is the most important insect pest of field peas (Maiteki et al.,1986; Soroka and Mackay,1990). Other legumes such as vetches, sweet peas, trefoil and beans are also attacked.
5. Life Cycle:
Some aphid species have very complicated life cycles. The life cycles may involve an 'alternation of host plants', sexual and asexual generations, and winged, migratory forms and wingless, stationary forms.
Reproduction may be live births without mating in summer and by mating and egg laying in fall. Aphids overwinter as eggs on a host plant. Wingless females or ‘stem mothers’ hatch from the eggs in the spring and in about 3 weeks give birth to 50-100 live female young. These may remain wingless or become winged for dispersal. These second-generation females will begin giving birth to live female young in about 2 weeks. This process will be repeated every 20-30 days for the rest of the summer. As the days become shorter and the temperatures lower, males will be produced and mating and egg laying will occur.
Most of the season, aphids reproduce without mating. They give birth to live aphids instead of laying eggs. The immature aphid usually closely resembles the adult female. It is not unusual to see aphids of several different sizes feeding on the same leaf.
Oddly, female aphids can give birth to live young that already have aphids developing in them. This helps to explain the phenomenal rates of reproduction of many aphid species.
An entire aphid colony can be produced from one aphid surviving a control program.
Winged forms develop under certain conditions.: i.e.,
The life cycle of the pea aphid illustrates the life cycles of the other members of the aphid group. Pea aphids overwinter as eggs on leaves and stems of various perennial legumes. In spring, when the plants resume growth, a small, light green, wingless female hatches from each egg. These aphids, which are all females called 'stem mothers', can reproduce without mating. They feed on the growing plants and give birth to female young. Some aphid of the second and third generations become winged and migrate to peas and other acceptable host plants. There they feed and produce wingless females that give rise to winged and wingless females.
Aphids develop from birth to maturity in 5-50 days depending on the weather. All pea aphids are female throughout spring and summer and a summer female can produce 50-150 young during her life. Whenever the host crop is cut during spring or summer, the winged aphids leave to search for new plants on which to live.
In late September or October, winged males and wingless females are produced. These mate and the females lay eggs. The eggs, which are deposited on leaves and stems, are yellow when first laid but soon turn green and then shiny black. There may be 7-15 generations per year.
Pea aphid eggs can survive low temperatures that kill other forms of the aphid. They overwinter as eggs on the crowns of clover or alfalfa (Anon., 1981).
Some female aphids can give birth to live young that already have aphids developing in them. This helps to explain the phenomenal rates of reproduction of many aphid species. Some workers have estimated that high populations of aphids can reach into the hundreds of millions of aphids per hectare (Dixon, 1973).
Most aphids like warm, humid growing conditions. These environmental conditions occur during periods of hot, rainy weather. They tend to promote severe aphid outbreaks.
Most aphids do not overwinter well on the prairies. Thus, most aphid infestations start as migrations on winds from the southern U.S. each summer. Because their reproductive potential is tremendous, large populations build up rapidly. Cool, moist conditions seem to favour aphid populations because food from plants is plentiful and predator and parasite activity is slowed. These conditions allow aphids to reproduce unchecked. Damage is often most evident during cool, dry weather, when plants are already under drought stress.
Some workers have suggested that rainfall, especially heavy showers, may be disastrous to aphid
populations, knocking them off their host plants. This may explain why so many species are adapted for feeding on the more protected undersides of leaves. Although heavy rainfall may be disastrous to aphid populations (e.g., Kriel et al., 1984), no studies were found in this review that documented specific mortality levels with specific rainfall amounts.
Kriel et al. (1 986) suggest that rainfall is not an adverse factor. They say that rainfall may knock aphids from the plants but they soon climb back up and, in so doing, may actually spread the infestation. Further, the host plant may flourish after a heavy rain, enhancing aphid population growth.
Wind may whip branches, causing the leaves to beat again each other and dislodge aphids. Wind also favours the rapid dispersal of aphids, sometimes over thousands of kilometers (Frazer, 1976).
Population overcrowding seems to initiate the development of winged aphids within a species. Host plant fluid conditions, temperature and photo period may also be important cues for some species.
8. Importance:
Grain aphids feed on cereals and grasses of various kinds. Direct damage to the crop is caused by sucking juices from the stems and leaves, removing valuable nutrients and causing fewer grain heads, lower numbers of kernel per head and reduced kernel weight.
High populations of aphids on developing heads before the dough stage will remove moisture from the kernels to produce light and shrunken grain. Once the kernels pass the milk stage, aphids are unable to pierce the bran and damage no longer occurs. Aphid populations of 50-70 per head or plant before the soft dough stage may require controls. Seventy English grain aphids per head of wheat before the soft dough stage will reduce yields. High populations of corn leaf aphid on barley cause severe damage before the boot stage but not after. For Russian wheat aphids, economic damage can result when as few as 10 percent of young plants or tillers are infested.
Most aphids can also carry and transmit barley yellow dwarf virus, a disease that can be important in barley and oat production. Barley yellow dwarf disease can reduce yields of dry forage and protein of oats and barley crops and reduce the height and number of tillers and as a result reduce grain yields.
Late-seeded barley and oats grown for green feed or silage are the most susceptible crops for virus infection because of aphid population build-up and the presence of a susceptible crop. The oat birdcherry aphid is the main vector for barley yellow dwarf virus on the prairies. Oat birdcherry aphid, carrying barley yellow dwarf virus, can reduce yields of dry forage and protein of oats and barley by over 50%.
Infestations may increase from 20% to 80% of the plants within 14 days, under optimum growing conditions.
The impact of aphid infestations on the economy of Manitoba may vary with the relative importance of the preferred host crops coupled with normal summer precipitation. Aphids may damage small grains by injecting toxic saliva into the leaves (Hewitt et al., 1984; Kriel et al., 1984; Fouche et al., 1984). Barley appears to be more susceptible to damage than wheat.
Aphid feeding on field peas reduces vegetative growth and nitrogen fixation (Maiteki and Lamb, 1985a). Feeding, at or soon after flowering, may reduce yields. The critical period is from the onset of flowering to pod formation.
Symptoms of injury may include one or more of the folowing: i.e.,
Yield losses of 90'% have been attributed to the some aphid infestations. Yield is most affected if high populations develop and serious damage occurs between the appearance of the flag leaf and the head. Plants under other stresses (e.g., drought) may be more adversely affected than young plants growing under optimum conditions. Pea aphids can be serious pests of field peas, the aphid populations peaking during pod formation (Maiteki et al., 1986).
Cereal diseases, including barley yellow dwarf virus, barley stripe mosaic virus, and brome mosaic virus, may be carried by some aphid species (Rybicki and von Wechmar, 1984; von Wechmar, 1984; vonWechmar and Rybicki, 1984).
Aphids feeding on a plant produce 'honeydew', a sticky excretion that favours the growth of sooty mould. This covering interferes with photosynthesis and transpiration.
Natural enemies of aphids are common throughout the world (Minks and Harrewijn, 1989). Bacteria, viruses, protozoa, fungi, nematodes, spiders, mites, ants, wasps, lady beetles, hover flies, lacewings, earwigs, big-eyed bugs, and other insects are known to attack aphids (Carroll and Hoyt, 1984). They usually keep populations of aphids under control. The presence of puffy, tan-coloured aphids, in fields, usually indicates the presence of a fungal disease of aphids. Fungal diseases usually occur during periods of cool, wet weather. This is also when aphid populations seem to surge.
II. MANAGEMENT
The key to aphid management is early detection through periodic scouting. A 10 or 2OX hand lens is needed to identify RWA when scouting in the field. The fields should be sampled weekly from the time of plant emergence to harvest. Populations may increase 2-3X between sampling, if checked biweekly.
If it is not possible to examine weekly throughout the growing season, ensure that the crop is examined weekly for the period of crop establishment. This is when the crop is most susceptible to damage. Later, the impact of aphids diminishes.
If strong southern winds occur over a period of several days, in the early summer, this may indicate a subsequent outbreak of aphids.
Remember that you have to look over the entire field. If the aphids fly in, they may land anywhere in the field. If they migrated in from an adjacent field, chances are that they will be found on the edge of the new field.
Look for symptoms of damage, including leaf discoloration in host plants. Severe infestations may appear as large, bronzy or brown patches in the field, often easily visible from the road. Later in the season, these patches may appear as thin stands.
In younger plants, aphids may cluster near the base of the ant, on the upper sides of the leaves. In older plants, check inside leaf whorls for the aphids. Collect plants by cutting the roots below the crown.
Infestation levels should be ranked. A sample ranking system is given below: i.e.,
You should also check for the presence of natural enemies. If most of the aphids are immobile and oddly coloured, they may be infected with a fungus or bacteria. If the aphids are darker than normal, they may be parasitized.
Predators may be moving among the aphids.
Researchers often use a network of special aphid suction traps to monitor aphid populations (Taylor, 1951; Johnson and Taylor, 1955).
Yellow sticky traps can also used to monitor winged aphids. Apparently, aphids are attracted to yellow most strongly because yellow leaves tend to have the most nutritious sap (Kennedy and Stroyan, 1959; Auclair, 1963).
Aphid control - whether it be cultural, biological or chemical should begin as soon as aphids are found on plants. Given their enormous reproductive potential and the damage that they can do, immediate attention is required.
Research has shown that there is no economic benefit in spraying for aphids after the crop has headed. The greatest reductions in yields of small grains is caused by heavy infestations prior to or just as the grain begins to head out.
Action threshold are based on sampling several locations throughout the field but they do not consider field or climatic conditions. Always check a large number of plants in all areas of the field.
Some thresholds for certain aphid species on small grains have been developed: i.e.,
English grain aphid........................ 30/stem - seedling stage
.......................................... 70/head - soft dough stag or earlier
Oat bird cherry aphid..................... 50/stem - boot to heading stage
Greenbug ....................................... 20/stem - seedling stage
.......................................... 30/stem - boot to heading
English grain aphids are probably the most important aphid affecting agriculture in Manitoba. When the English grain aphid moves into the heads of grain, sampling should be done carefully on about 100 grain heads from different parts of a field. If the infestation averages 40-50 aphids/head, control is probably justified. Populations of 70 aphids/head can reduce kernel weights of wheat in the milk and early dough stages by 8%.
Remember that these thresholds are somewhat arbitrary. Some workers in other jurisdictions consider 10-15 aphids/plant to be a potentially serious infestation.
On peas, the threshold is greater than 2-3 pea aphids /20-cm plant tip at flowering (Maiteki and Lamb,1985b). Plants, infested before the flowers open, recover without loss of yield. Sampling should be done when 50-75% of the plants are in flower (Timlick and Turnock, 1991).
On alfalfa, 19-20 pea aphids/stem is considered the economic threshold in North Dakota.
Populations of 20-30 greenbugs/stem, on seedling plants, can reduce yield by as much as 60%. Higher populations can kill plants. Greenbugs inject toxin into plant. Toxin and feeding can damage leaves, retard root growth, and can cause stunting, abnormal tillering, and improper filling of heads.
Obviously, one should consider several factors (e.g., the aphid density on the specific crop, the current weather conditions, the presence and abundance of natural enemies, the value of the crop, the stage of the crop being attacked, and the time to harvest) before making a decision to apply an insecticide.
Good crop management is essential. Any practice that reduce crop stresses should be emphasized (e.g., good seed bed preparation, proper seedling rate, fertilization, irrigation where available). On irrigated alfalfa, control may be unnecessary if adequate water is provided to the plants.
Easy-seeded crops grow and become vigorous and pass the susceptible stage before aphid populations reach
damaging levels.
Volunteer grain control is also critical. When controlling aphid-infested grasses or volunteer grains, either by mechanical or herbicide means, the aphids should first be treated with an insecticide to prevent them from moving out of the localized, infested areas. A tank-mix of herbicide and insecticide would be the most efficient approach.
If only mechanical control is used on the grasses and volunteer grains, the first 10-20 rows of adjacent plantings should be treated to control aphids as they move out of tilled areas.
Insecticides used for aphid control should be applied before the plants are severely damaged. Farmers should keep careful check on the build-up of aphid populations in their fields. One properly timed application of insecticide per season usually gives satisfactory control. Timing to prevent injury to pollinators in seed fields is very important.
Chemical controls are effective when carried out before the most susceptible crop stage is reached. Several factors to consider before planning a control program are (a) the species of aphid and its abundance, (b) the stage of development of the crop, (c) the presence of natural enemies, and (d) the potential crop value.
Some kinds of aphids have become resistant to most insecticides on the market. Whatever product is used, one should be careful to ensure complete coverage of the plant. Any aphids that escape treatment will soon produce new aphids to replace those killed in the earlier treatment.
Aphids are one of the most difficult insects to manage because of their remarkable reproductive ability. The females do not mate or lay eggs during the summer. They are parthenogenic and give birth to live young. If even one aphid survives an insecticide application (and some always do) then she can generate a new colony and reinfest the crop.
Although some insecticide labels suggest that 2-3 applications of an approved insecticide, applied at weekly intervals, will control an infestation, it is rarely necessary to spray for aphids more than once in Manitoba.
To minimize the risk of resistance developing in the aphids, use a different type of insecticide for each of these treatments. If more than 2 or 3 treatments are necessary, be sure to rotate the use of the insecticides.
The first insecticide application should be possible using field sprayers, calibrated to deliver 20 to 30 U.S. gal./acre. The second application would probably require aerial spraying.
Protection of the flag leaf is the key objective because of its importance to yield.
Insecticides Registered for Use on Peas
Maiteki and Lamb (1985b) showed that malathion (0.6-0.9 1/acre), applied when pods first form, protects pea yield better than earlier or later applications. The young pod stage is most sensitive to pea aphid damage. Do not apply to peas in bloom.
Dimethoate is also registered for the control of aphids on peas and beans. The pro-harvest interval is 3 days for peas and 7 days for beans. It can be applied from the ground or the air.
Methomyl (Lannate [0.9 1/acre]) is also registered for the control of pea aphids on peas. There is a 1-day pre-harvest interval. Lannate may be applied by air or ground equipment. It works as a contact and stomach poison with some systemic action. It has quick knock down but short residual activity. Apply when insects exceed threshold levels in sufficient water for good coverage. Use higher rates for mature insects, dense canopy or when infestations are heavy. When mixing, fill spray tank 1/4- to 1/2- full of water and add Lannate L directly to spray tank. Mix thoroughly. Once dissolved, continued agitation is not required. Do not use air agitation. Sprays or drift must not contact workers, other persons or animals. The area being treated must be vacated by unprotected persons. Lannate is of high acute mammalian toxicity. It may be fatal or cause blindness if swallowed. Do not apply to areas being visited by bees. Time applications to coincide with minimum bee activity.
Pirimicarb (Pirimor WP [0.06 - 0.11 kg/acre]) is registered for the control of pea aphids on peas. There is a 6-day pre-harvest interval. It may be applied by air or ground equipment. It works as a contact, vapour and has localized systemic action. Use higher rates when insect populations are high or when very cool weather is prevailing.
Insecticides Registered for Use on Field Crops
In Alberta, Saskatchewan and Manitoba, dimethoate (e.g., Cygon 480 or Sys-tem 480), a systemic insecticide, and malathion (e.g., Malathion 500), a contact insecticide, are recommended for the control of aphids in cereal crops.
Control occurs within 2 days and lasts for about 9 days (Harper, 1978). The pre-harvest use interval is 21 days for dimethoate and 7 days for malathion.
Dimethoate, being systemic, may be more effective in controlling aphids that are well-protected (i.e., indense foliage) from direct spraying.
Mediocre aphid control can be expected under certain conditions: i.e.,
The application rates and pre-harvest intervals for some insecticides commonly-used against aphids in grains are given below: i.e.,
Rate Preharvest
(g Al/ha) Interval
Barley, Oat, Rye
& Wheat
Demeton......... 210 45
Dimethoate...... 210 21
Malathion....... 700 7
Corn
Malathion...... 1000-1400 5
Restrictions -
Malathion: Do not apply at air temperatures below 20 C.
Demeton: Do not use on rye.
Insecticides Registered for Use on Alfalfa
The application rates and pre-harvest intervals for some insecticides commonly-used against aphids on alfalfa are given below: I.e.,
Rate Preharvest
(g Al/ha) Interval
Demeton
(for hay).......... 280-325 21
Dimethoate......... 210 2
Malathion.......... 700 7
Methidathion....... 280-560 10
Use 90-110 L water/ha to ensure thorough coverage. Treat if population is large enough to stunt plants or if heavily infested hay is to be dehydrated.
When using methidathion (Supracide [0.5-0.9 1/acre]), note that there is a 10-day pre-harvest interval. It may be applied by air or ground equipment. Toxic to birds, bees, fish and other wildlife. Observe a 100m setback from any body of water or environmentally-sensitive area when applying by air. Do not apply to crops in bloom. Do not enter treated fields on the same day of application.
When using dimethoate, remove any cattle that might be present prior to spraying. Do not treat when bees are foraging. Do not apply to alfalfa in full bloom. Note that dimethoate has to be stored at above-freezing temperatures during the winter.
Note that disulfoton (e.g., DI-Syston [6-9 kg/acre using the granular formulation or 1.1 -1.9 1/acre using the liquid concentrate]), a systemic insecticide, is registered for the control of aphids on potatoes. There is a 90-day pre-harvest interval. For granular applications, place the granules in the seed furrow or in a band on each side of the seed furrow at planting. Applications may also be made as a side dressing, either above or with fertilizer, after plants become established. Use the higher rates in organic soils. For liquid applications, apply as a water emulsion or with liquid fertilizer as an in-furrow spray or injection on each side of the seed furrow at planting, or inject as a side-dressing after plants become established. Use the higher rates in organic soils.
Oxydemeton-methyl (Metasystox-R [0.7-0.9 1/acre]) is also registered for aphids in seed alfalfa. It maybe applied by air or found equipment. To mix, pour the required amount of Metasystox-R into full amount of water and then agitate. It works as a contact a systemic poison. Do not use alfalfa or its seed for food, feed, or forage.
Insecticides Registered for Use on Potatoes
Aphids on potatoes can be controlled using carbofuran (Furadan 48OF [0.44.5 1/acre]). There is a 7-day pre-harvest interval.
They also can be controlled on potatoes with Lannate. Note the precautions and restrictions regarding this product noted above under 'Insecticides Registered for Use on Peas'.
Aphids on potatoes can also be controlled using malathion (0.6-0.9 1/acre), applied from the ground or air. It works as a contact poison. Apply when insect numbers exceed economic threshold levels insufficient water for good coverage. Use higher rates for heavy infestations, dense canopy or mature aphids. Apply only when daytime temperatures are above 18C.
Potato aphids on potatoes can also be controlled using pirimicarb (e.g., Pirimor [0.172-0.222 kg/acre]). There is a 7-day pre-harvest interval. It may be applied by air or ground equipment.
Phorate (Thimet granules [140-215 g/100 m row]) is also registered for the control of aphids on potatoes. The pre-harvest interval is not applicable. Distribute granules evenly in furrow or granules may be banded on each side of the row at planting time. Use the low rate for sandy or light soils and the high rate for silt or heavy soils. Thimet works as a systemic poison with effective initial residual activity on soil and foliar insects. Note that it is highly toxic to fish, birds and other animals.
Endosulfan (Thiodan [0.6 I/acre]) is also registered for the control of aphids on potatoes. There is no pre-harvest interval. It may be applied by air or ground equipment. Do not apply or allow to drift to areas occupied by unprotected persons and animals, or to reams, lakes or ponds.