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SPINACH POST EMERGENCE PEST CONTROL By Tim Braun
Spinach has become a big part of the fresh vegetable market. The fresh vegetable market caters to the needs of
consumers for salads. Any type of contamination of the spinach leafs that go into this market is not allowed by
produce buyers.
The contamination includes weeds, discolored leaves, dirt from dust and insects. Beneficial insects are considered to be
a contaminate when found in harvested fresh spinach. Beneficial insects that form webbing and pupate on the leaves
contaminate spinach. The aphid dead bodies found after beneficial wasps have laid their eggs in them are considered a
contaminate of fresh spinach.
.Green Peach And Potato Aphids There are two major aphid insect pests that affect the spinach crop. The potato
aphid and the green peach aphid. The potato aphid is a larger aphid than the green peach aphid and it is not as active on
spinach as the green peach aphid.
The body of the potato aphid is longer than the green peach aphid and can be pink or green. The potato aphid can be
found in colonies with the green peach aphid or by themselves. Potato aphid adult occur alone or with clusters of
young aphids with them.
Aside from the fact that potato aphids are larger than green peach aphids the other body part that is different is the
tubercles of the two aphids. Tubercles are found inside the base of the aphid antenna. The tubercle of the potato aphid
slope to the outside and the green peach aphid tubercles converge toward one another. The green peach aphid colonies
tend to start at the bottom of the plant whereas the potato aphids are found all through the plant.
The green peach aphid is green unlike the potato aphid which can be green and pink. Of the two aphids the green
peach is more of a problem on spinach. Both aphids when in high numbers stunt the spinach and will contaminate the
crop. Green peach aphids carry some viruses that can affect spinach.
The green peach aphid reproduces asexually and sexually. Most of the green peach aphids reproduce asexually.
Asexual reproduction occurs when females give birth without mating. Sexual reproduction in aphids occurs when male
and female mate. The result of asexual reproduction is a great many active aphids in a very short time period. The
young aphids grow to adulthood in 4 to 5 days.
With their piercing sucking mouthparts the aphids stick their mouthparts into the plant tissue and sucks out the plant
fluids. This is usually into the phloem that carries the spinach life supporting sugars to vital growth areas of the plant.
This can cause stunting and plant deformity. During this feeding process the green peach aphid can be inserting virus
diseases.
While feeding on the plant in this manner the aphid produces large amounts of excrement. This excrement, honey
dew, produced by the aphids and dropped onto the leaves causing fungus and molds to grow. The result is a
contamination of the spinach that cannot be shipped to market.
When monitoring for aphids the edges of the field should be checked for aphids. The aphids first appear on the edges
of the field. They will sometimes be found in the edges of bare spots within the field.
There are several beneficial insects that feed on the aphid. Certain wasps insert their eggs into aphids that produce
larvae that kill the aphid. A fungus, Entomophthora aphidis, can kill some of the aphid population. The beneficial
enemies are not numerous enough to protect the kind of spinach production needed by today’s growers.
The organic control methods include insecticide soap sprays. Cultural control methods include tents or covers and by
controlling nitrogen excesses. Aphid populations multiply on spinach plants that contain excess nitrogen. Monitoring
the soil for excess nitrogen with soil nitrate quick tests will determine nitrate excesses immediately. Soil nitrate levels
for spinach become excessive when they test over 100 to 120 parts per million.
The use of the following insecticides have been approved for spinach: Diazinon in different formulations, Dimethoate,
and Thiodan. Admire can be applied pre-plant. Read and follow label directions.
Leaf miners Adults hatch from pupa in the soil. They mate and lay their eggs in the leaf tissue of spinach. The
larvae hatch and continue growing and feeding between the upper and lower parts of the leaf. The area tunnels inside
the leaf made by the leaf minor are referred to as leaf mines.
The larvae grows inside the mines. In the process the mines are enlarged. At maturity the larvae cut a hole in the leaf
and either pupate on the leaf forming a pupal case or in most cases the larvae drop to the soil and pupate in cracks in
the soil.
This leaf damage results in a reduction of the spinach plants photosynthesis. The leaf miner larvae leaves fecal matter
in the leaf mine. This contamination reduces the market value of the spinach.
Leaf miners are usually not a problem, but like any other pest they can multiply under the right conditions. When the
small spinach seedlings have four to five leaves with high populations of leaf miners, control measures may be
necessary.
There are natural predators for the leaf miner. Because leaf miners live inside the leaf, predators are limited in their
control of them. Parasite wasps can insert eggs into the leaf miner larvae then the hatched wasp larvae kills the leaf
miner larvae.
Disking recently harvested adjacent fields that had high populations of leaf miners will reduce the pest.
The chemical control includes: Agri-Mek 0.1.5 EC (Check with your farm advisors because of limitations on this
product). Agri-Mek will kill the leaf miner larvae in the leaf.; TriGard is a growth regulator that is effective against leaf
miners. The product called Neemix only kills the leaf miner pupae. It does reduce future populations. Neemix in a
restricted use product for organic farming
There are certain insecticides that kill the predators of leaf miners. The loss of these predators of leaf miners can cause
economic damage to the spinach crop. Insecticides that can kill the predators of leaf miners include: Lannate, Pounce
and Ambush.
Cabbage Looper (caterpillar) This is one of the major pests of spinach. Cabbage looper can show up in harvested fresh
vegetables and they also inhabit fresh harvested spinach unless controlled. The holes that cabbage looper make in
spinach leaves and the fecal matter produced by them reduce the marketability. Cabbage looper are green in color with
a narrow white stripe along each side. They have several white lines on their backs.
. When looper caterpillars move across a surface they form a loop with their body by arching their back. The
adult is a brown winged moth with mottled front wings. The adult cabbage looper has a small silver figure like an 8 on
its wings.
The eggs that cabbage looper adults lay are on the bottom of the older spinach leaves. These eggs are dome shaped.
The looper eggs start out white but get darker as they approach hatching. The looper eggs have a surface with light
ridges. The corn earworm has the same dome shape, but it has deeper ridges on the egg surface.
Corn Earworm The color of corn earworm is variable with stripes. Corn earworms have one or two prominent
hairs on their backs. On the backs of corn earworms are rows of nodules or swellings that are referred to as tubercles.
When corn earworm eggs are first laid they are white. Then a dark red to brown colored ring forms around the top of
the corn earworm egg. The egg will turn dark just before the egg hatches.
Cutworm There are three types of cutworm that feed on spinach. Black greasy cutworm larvae have black bumps
or tubercles on each segment of their body. The black greasy cutworm has a greasy gray to brown color. Tunnels in
the soil are made by the black greasy cutworm. The tunnels in the soil are where the black greasy cutworm takes the
plants that it cuts off above the soil.
The granulate cutworm does not make tunnels in the soil and it has a variety of skin colors that are lighter than the
black greasy cutworm.
The larva of the variegated cutworm is yellow to brown with four to six diamond shaped spots on its back. These
spots are in a line and they are dull yellow and pink colored. The front wings of the adult are dark gray or brown with
irregular spots or bands. The hind wings are of a lighter color.
Beet Armyworms The adult beet armyworm lay their eggs in groups of 50 to 75 eggs. They cover these eggs
with white scales from their bodies. The egg mass then looks like a cotton mass. The larvae that hatch are green in
color with light colored bands on their back and a broad stripe down each side. While the young larvae is feeding they
will spin a web over themselves on the underside of the leaf.
The young armyworm begin feeding together but as they mature they feed alone. They can travel to many plants
causing damage and contamination. Their entire life cycle can last 36 days in 80 F. degree weather.
Western Yellow Striped Armyworm
Even though the western yellow striped armyworm is an occasional pest in spinach it will make itself known by the
large amount of damage that it can produce. The western yellow striped armyworm has an complete lifespan of around
54 days. Adult 17 days; egg 4 days: larva 18 days; and pupa 15 days.
The adult yellow striped armyworm lays 200 to 500 eggs in masses covering them with body scales. The larvae can
grow to be one and a half inches long or more. The color of the larvae is black with two lines of yellow stripes down
each side. The larvae will skeletonize the plants, but they may consume the entire above ground parts of young plants.
Western yellow striped armyworm can do this in a very short period of time.
Caterpillar Pest Control The above army worms, cut worms, corn earworms and loopers are classified as
caterpillars. Biological control of caterpillars includes the wasp parasites. Caterpillars are susceptible to virus diseases.
The cultural controls for caterpillars include destroying host weeds near the spinach fields. By disking shortly after the
crop has been harvested caterpillar worms, pupae and eggs are destroyed.
When monitoring fields for caterpillars the period right after the spinach seedlings first emerge from the soil is a critical
period. Check for egg masses. Try to have most of the eggs hatched before making applications of any pesticide.
Fields with emerging seedling should be monitored twice per week.
Chemical control includes the following: Bts, Bacillus Thuringiensis (Dipel, Thuricide and many other formulations).
Bts are bio pesticides that when eaten by the caterpillars produces a toxin that kills. Bts can produce spores in the
caterpillar body that multiply and cause septicemia that kills the larva. This material is easy on predators. Bts are very
specific. Bts can be used by organic growers. The younger the larva the better the control with Bts.
Lannate is a carbamate insecticide and nematicide. Lannate is both a contact and a systemic insecticide. It is a stomach
poison.
The permethrins Pounce and Ambush are contact and stomach poisons. The same precautions on leaf miners applies
to these two chemical pesticides.
Success (spinosad) gives a quick knockdown of caterpillars. Effective on armyworms when they are small. Success
has to be eaten by the larvae to be effective. Success has low toxicity to predacious insects.
Confirm is a growth regulator. This growth regulator is safe to use where predacious insects are needed. Confirm is
long lasting but new growth should be treated. To prevent insect immunity the label says: “Not to be used on more
than 3 generations of a pest.”
Caterpillars must feed on the pesticide Larvin. It is a weak contact killer. It is an oxime carbamate inceticide/ovicide.
When spinach has dense foliage and there is a heavy
infestation of caterpillars the higher label dosage is required for control.
Diazinon is an organophosphate insecticide. Diazinon is both an insecticide and miticide. Being a stomach poison as
well as a contact pesticide Diazinon can control caterpillars when eaten or when applied to their bodies.
Spinach Crown Mites Spinach crown mites damage new leaves at the heart of the plant. The spinach crown mites
are very small and transparent. The damage of crown mites is outgrown by the spinach plant unless the plant is
growing slowly. Crown mites can injure the plant to the point where diseases can infect the spinach. Dust will dry out
the spinach plant and allow spinach crown mite to multiply.
When high populations of crown mites occur and predators are not able to control them, miticides are available. The
pesticides that are available include: Agri-Mek; Thiodan and Neemix.
Damping Off Disease Damping off disease is usually overcome with the use of disease resistant spinach plants, seed
treatments and preplant soil treatments. Damp off can occur throughout the growth of the spinach crop. The disease is
caused by several soil fungi including: Fusarium, Pythium and Rhizoctonia.
Post emergence control of damp off disease is controlled by good water management. Never let water stand in the
field. Excess water can cause the same damage with of without a fungi pathogen. The damage includes brown water
soaked roots with some top plant curling of the leaves. Damp off damage to mature plants can cause stunting and
death.
Downy mildew One of the most important diseases in spinach is the downy mildew or blue mold. Spinach does
well in cool, damp conditions. These are the same conditions that downy mildew does best in. The spinach is grown
during the fall, winter and spring months when conditions are usually cool. The damp weather is provided with
sprinkler irrigation systems when rain isn’t available. The spinach itself provides plenty of humidity with its lush
growth of leaves.
The first signs of an infection by downy mildew are yellow spots on the leaves. These spots become darker and dry
out. Spores form on the bottom of the leaf that have a blue cast to them.
Within the spinach downy mildew species there are many variations that infect newly produced spinach plants that are
resistant to the older disease species.
When treating for downy mildew in spinach, applications should be made before the mildew appears. Once the field is
infested efforts to contain it and control are almost impossible. Ridomil Gold/Copper WP as a foliage application has
been effective against downy mildew in spinach. Aliette 80 WDG can be used as an alternate to reduce mildew
immunity to other treatments.
Anthracnose Applying prevention copper sprays to spinach fields likely to be infested with anthracnose is the only
recommended chemical spray. The post emergence prevention efforts of controlling anthracnose include reducing the
use of excess sprinkler irrigation.
Other diseases that infest spinach include: Cladoporium leaf spot and Stemphuylium leaf spot. Both of these diseases
have been treated with the preventative copper fungicides, but when the infection is severe copper fungicides are
ineffective.
Colors of the infection spots can be used to distinguish these spinach diseases.
Downy mildew has purple spots. Anthracnose has black fruiting bodies inside circular spots. Cladoporium has dark
green spots. Stemphuylium has circular tan papery spots.
Post Emergence Spinach Weed Control There are two herbicides that can be used post emergence on spinach.
The herbicide, Spin-Aid, can only be used on spinach grown for processing or seed. Spin-Aid is a contact herbicide
that controls some of the broad leaved weeds and grasses in spinach. Apply when the seedlings are small. Some
damage can occur to the spinach.
Poast a systemic herbicide that is specific for grasses can be used until 2 weeks before harvest. Poast may also result
in some damage to the spinach. Poast will not control annual bluegrass.
The use of trade names in this course 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. Use pesticides safely. Read and follow directions on the manufacturer’s label.
Acknowledgements:
http://www.ipmcenters.org/cropprofiles/docs/NJspinach.html
www.ipm.ucdavis.edu/PMG/selectnewpest.spinach.
Nick Laminski Grower Solutions Magazine"http://www.lefroy-valley.com.au/"
Biology-Pages.Info Kimball's Biology Pagesa
Spinach has become a big part of the fresh vegetable market. The fresh vegetable market caters to the needs of
consumers for salads. Any type of contamination of the spinach leafs that go into this market is not allowed by
produce buyers.
The contamination includes weeds, discolored leaves, dirt from dust and insects. Beneficial insects are considered to be
a contaminate when found in harvested fresh spinach. Beneficial insects that form webbing and pupate on the leaves
contaminate spinach. The aphid dead bodies found after beneficial wasps have laid their eggs in them are considered a
contaminate of fresh spinach.
.Green Peach And Potato Aphids There are two major aphid insect pests that affect the spinach crop. The potato
aphid and the green peach aphid. The potato aphid is a larger aphid than the green peach aphid and it is not as active on
spinach as the green peach aphid.
The body of the potato aphid is longer than the green peach aphid and can be pink or green. The potato aphid can be
found in colonies with the green peach aphid or by themselves. Potato aphid adult occur alone or with clusters of
young aphids with them.
Aside from the fact that potato aphids are larger than green peach aphids the other body part that is different is the
tubercles of the two aphids. Tubercles are found inside the base of the aphid antenna. The tubercle of the potato aphid
slope to the outside and the green peach aphid tubercles converge toward one another. The green peach aphid colonies
tend to start at the bottom of the plant whereas the potato aphids are found all through the plant.
The green peach aphid is green unlike the potato aphid which can be green and pink. Of the two aphids the green
peach is more of a problem on spinach. Both aphids when in high numbers stunt the spinach and will contaminate the
crop. Green peach aphids carry some viruses that can affect spinach.
The green peach aphid reproduces asexually and sexually. Most of the green peach aphids reproduce asexually.
Asexual reproduction occurs when females give birth without mating. Sexual reproduction in aphids occurs when male
and female mate. The result of asexual reproduction is a great many active aphids in a very short time period. The
young aphids grow to adulthood in 4 to 5 days.
With their piercing sucking mouthparts the aphids stick their mouthparts into the plant tissue and sucks out the plant
fluids. This is usually into the phloem that carries the spinach life supporting sugars to vital growth areas of the plant.
This can cause stunting and plant deformity. During this feeding process the green peach aphid can be inserting virus
diseases.
While feeding on the plant in this manner the aphid produces large amounts of excrement. This excrement, honey
dew, produced by the aphids and dropped onto the leaves causing fungus and molds to grow. The result is a
contamination of the spinach that cannot be shipped to market.
When monitoring for aphids the edges of the field should be checked for aphids. The aphids first appear on the edges
of the field. They will sometimes be found in the edges of bare spots within the field.
There are several beneficial insects that feed on the aphid. Certain wasps insert their eggs into aphids that produce
larvae that kill the aphid. A fungus, Entomophthora aphidis, can kill some of the aphid population. The beneficial
enemies are not numerous enough to protect the kind of spinach production needed by today’s growers.
The organic control methods include insecticide soap sprays. Cultural control methods include tents or covers and by
controlling nitrogen excesses. Aphid populations multiply on spinach plants that contain excess nitrogen. Monitoring
the soil for excess nitrogen with soil nitrate quick tests will determine nitrate excesses immediately. Soil nitrate levels
for spinach become excessive when they test over 100 to 120 parts per million.
The use of the following insecticides have been approved for spinach: Diazinon in different formulations, Dimethoate,
and Thiodan. Admire can be applied pre-plant. Read and follow label directions.
Leaf miners Adults hatch from pupa in the soil. They mate and lay their eggs in the leaf tissue of spinach. The
larvae hatch and continue growing and feeding between the upper and lower parts of the leaf. The area tunnels inside
the leaf made by the leaf minor are referred to as leaf mines.
The larvae grows inside the mines. In the process the mines are enlarged. At maturity the larvae cut a hole in the leaf
and either pupate on the leaf forming a pupal case or in most cases the larvae drop to the soil and pupate in cracks in
the soil.
This leaf damage results in a reduction of the spinach plants photosynthesis. The leaf miner larvae leaves fecal matter
in the leaf mine. This contamination reduces the market value of the spinach.
Leaf miners are usually not a problem, but like any other pest they can multiply under the right conditions. When the
small spinach seedlings have four to five leaves with high populations of leaf miners, control measures may be
necessary.
There are natural predators for the leaf miner. Because leaf miners live inside the leaf, predators are limited in their
control of them. Parasite wasps can insert eggs into the leaf miner larvae then the hatched wasp larvae kills the leaf
miner larvae.
Disking recently harvested adjacent fields that had high populations of leaf miners will reduce the pest.
The chemical control includes: Agri-Mek 0.1.5 EC (Check with your farm advisors because of limitations on this
product). Agri-Mek will kill the leaf miner larvae in the leaf.; TriGard is a growth regulator that is effective against leaf
miners. The product called Neemix only kills the leaf miner pupae. It does reduce future populations. Neemix in a
restricted use product for organic farming
There are certain insecticides that kill the predators of leaf miners. The loss of these predators of leaf miners can cause
economic damage to the spinach crop. Insecticides that can kill the predators of leaf miners include: Lannate, Pounce
and Ambush.
Cabbage Looper (caterpillar) This is one of the major pests of spinach. Cabbage looper can show up in harvested fresh
vegetables and they also inhabit fresh harvested spinach unless controlled. The holes that cabbage looper make in
spinach leaves and the fecal matter produced by them reduce the marketability. Cabbage looper are green in color with
a narrow white stripe along each side. They have several white lines on their backs.
. When looper caterpillars move across a surface they form a loop with their body by arching their back. The
adult is a brown winged moth with mottled front wings. The adult cabbage looper has a small silver figure like an 8 on
its wings.
The eggs that cabbage looper adults lay are on the bottom of the older spinach leaves. These eggs are dome shaped.
The looper eggs start out white but get darker as they approach hatching. The looper eggs have a surface with light
ridges. The corn earworm has the same dome shape, but it has deeper ridges on the egg surface.
Corn Earworm The color of corn earworm is variable with stripes. Corn earworms have one or two prominent
hairs on their backs. On the backs of corn earworms are rows of nodules or swellings that are referred to as tubercles.
When corn earworm eggs are first laid they are white. Then a dark red to brown colored ring forms around the top of
the corn earworm egg. The egg will turn dark just before the egg hatches.
Cutworm There are three types of cutworm that feed on spinach. Black greasy cutworm larvae have black bumps
or tubercles on each segment of their body. The black greasy cutworm has a greasy gray to brown color. Tunnels in
the soil are made by the black greasy cutworm. The tunnels in the soil are where the black greasy cutworm takes the
plants that it cuts off above the soil.
The granulate cutworm does not make tunnels in the soil and it has a variety of skin colors that are lighter than the
black greasy cutworm.
The larva of the variegated cutworm is yellow to brown with four to six diamond shaped spots on its back. These
spots are in a line and they are dull yellow and pink colored. The front wings of the adult are dark gray or brown with
irregular spots or bands. The hind wings are of a lighter color.
Beet Armyworms The adult beet armyworm lay their eggs in groups of 50 to 75 eggs. They cover these eggs
with white scales from their bodies. The egg mass then looks like a cotton mass. The larvae that hatch are green in
color with light colored bands on their back and a broad stripe down each side. While the young larvae is feeding they
will spin a web over themselves on the underside of the leaf.
The young armyworm begin feeding together but as they mature they feed alone. They can travel to many plants
causing damage and contamination. Their entire life cycle can last 36 days in 80 F. degree weather.
Western Yellow Striped Armyworm
Even though the western yellow striped armyworm is an occasional pest in spinach it will make itself known by the
large amount of damage that it can produce. The western yellow striped armyworm has an complete lifespan of around
54 days. Adult 17 days; egg 4 days: larva 18 days; and pupa 15 days.
The adult yellow striped armyworm lays 200 to 500 eggs in masses covering them with body scales. The larvae can
grow to be one and a half inches long or more. The color of the larvae is black with two lines of yellow stripes down
each side. The larvae will skeletonize the plants, but they may consume the entire above ground parts of young plants.
Western yellow striped armyworm can do this in a very short period of time.
Caterpillar Pest Control The above army worms, cut worms, corn earworms and loopers are classified as
caterpillars. Biological control of caterpillars includes the wasp parasites. Caterpillars are susceptible to virus diseases.
The cultural controls for caterpillars include destroying host weeds near the spinach fields. By disking shortly after the
crop has been harvested caterpillar worms, pupae and eggs are destroyed.
When monitoring fields for caterpillars the period right after the spinach seedlings first emerge from the soil is a critical
period. Check for egg masses. Try to have most of the eggs hatched before making applications of any pesticide.
Fields with emerging seedling should be monitored twice per week.
Chemical control includes the following: Bts, Bacillus Thuringiensis (Dipel, Thuricide and many other formulations).
Bts are bio pesticides that when eaten by the caterpillars produces a toxin that kills. Bts can produce spores in the
caterpillar body that multiply and cause septicemia that kills the larva. This material is easy on predators. Bts are very
specific. Bts can be used by organic growers. The younger the larva the better the control with Bts.
Lannate is a carbamate insecticide and nematicide. Lannate is both a contact and a systemic insecticide. It is a stomach
poison.
The permethrins Pounce and Ambush are contact and stomach poisons. The same precautions on leaf miners applies
to these two chemical pesticides.
Success (spinosad) gives a quick knockdown of caterpillars. Effective on armyworms when they are small. Success
has to be eaten by the larvae to be effective. Success has low toxicity to predacious insects.
Confirm is a growth regulator. This growth regulator is safe to use where predacious insects are needed. Confirm is
long lasting but new growth should be treated. To prevent insect immunity the label says: “Not to be used on more
than 3 generations of a pest.”
Caterpillars must feed on the pesticide Larvin. It is a weak contact killer. It is an oxime carbamate inceticide/ovicide.
When spinach has dense foliage and there is a heavy
infestation of caterpillars the higher label dosage is required for control.
Diazinon is an organophosphate insecticide. Diazinon is both an insecticide and miticide. Being a stomach poison as
well as a contact pesticide Diazinon can control caterpillars when eaten or when applied to their bodies.
Spinach Crown Mites Spinach crown mites damage new leaves at the heart of the plant. The spinach crown mites
are very small and transparent. The damage of crown mites is outgrown by the spinach plant unless the plant is
growing slowly. Crown mites can injure the plant to the point where diseases can infect the spinach. Dust will dry out
the spinach plant and allow spinach crown mite to multiply.
When high populations of crown mites occur and predators are not able to control them, miticides are available. The
pesticides that are available include: Agri-Mek; Thiodan and Neemix.
Damping Off Disease Damping off disease is usually overcome with the use of disease resistant spinach plants, seed
treatments and preplant soil treatments. Damp off can occur throughout the growth of the spinach crop. The disease is
caused by several soil fungi including: Fusarium, Pythium and Rhizoctonia.
Post emergence control of damp off disease is controlled by good water management. Never let water stand in the
field. Excess water can cause the same damage with of without a fungi pathogen. The damage includes brown water
soaked roots with some top plant curling of the leaves. Damp off damage to mature plants can cause stunting and
death.
Downy mildew One of the most important diseases in spinach is the downy mildew or blue mold. Spinach does
well in cool, damp conditions. These are the same conditions that downy mildew does best in. The spinach is grown
during the fall, winter and spring months when conditions are usually cool. The damp weather is provided with
sprinkler irrigation systems when rain isn’t available. The spinach itself provides plenty of humidity with its lush
growth of leaves.
The first signs of an infection by downy mildew are yellow spots on the leaves. These spots become darker and dry
out. Spores form on the bottom of the leaf that have a blue cast to them.
Within the spinach downy mildew species there are many variations that infect newly produced spinach plants that are
resistant to the older disease species.
When treating for downy mildew in spinach, applications should be made before the mildew appears. Once the field is
infested efforts to contain it and control are almost impossible. Ridomil Gold/Copper WP as a foliage application has
been effective against downy mildew in spinach. Aliette 80 WDG can be used as an alternate to reduce mildew
immunity to other treatments.
Anthracnose Applying prevention copper sprays to spinach fields likely to be infested with anthracnose is the only
recommended chemical spray. The post emergence prevention efforts of controlling anthracnose include reducing the
use of excess sprinkler irrigation.
Other diseases that infest spinach include: Cladoporium leaf spot and Stemphuylium leaf spot. Both of these diseases
have been treated with the preventative copper fungicides, but when the infection is severe copper fungicides are
ineffective.
Colors of the infection spots can be used to distinguish these spinach diseases.
Downy mildew has purple spots. Anthracnose has black fruiting bodies inside circular spots. Cladoporium has dark
green spots. Stemphuylium has circular tan papery spots.
Post Emergence Spinach Weed Control There are two herbicides that can be used post emergence on spinach.
The herbicide, Spin-Aid, can only be used on spinach grown for processing or seed. Spin-Aid is a contact herbicide
that controls some of the broad leaved weeds and grasses in spinach. Apply when the seedlings are small. Some
damage can occur to the spinach.
Poast a systemic herbicide that is specific for grasses can be used until 2 weeks before harvest. Poast may also result
in some damage to the spinach. Poast will not control annual bluegrass.
The use of trade names in this course 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. Use pesticides safely. Read and follow directions on the manufacturer’s label.
Acknowledgements:
http://www.ipmcenters.org/cropprofiles/docs/NJspinach.html
www.ipm.ucdavis.edu/PMG/selectnewpest.spinach.
Nick Laminski Grower Solutions Magazine"http://www.lefroy-valley.com.au/"
Biology-Pages.Info Kimball's Biology Pagesa
 | |  |