biology of economic agriculture

1. Corn Pest

2. Corn leaf aphid
Rhopalosiphum maidis

3. Taxonomy
Common name: Cornleaf aphid
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Superfamily: Aphidoidea
Subfamilies: Eriosomatidae
Genus: Rhopalosiphum
Scientific name: maidis

4. Description
 oval wingless adult is approx.
 2 mm long
 Pale bluish-green with black antennae
 Legs, and cornicles and a dark area around the
base of the cornicles
 The head is marked with two longitudinal dark
bands, and the abdomen with a row of black
spots on each side
 The body have a powdery coating. The winged
form is about the same size.
 Host plan usually cereal crop
(maize,wheat,barley)

5. Symptom
 First it will colonize whorl leaves and immature
tassel.
 Will attack pollen shed and stunt the plant.
 Maize dwarf mosaic virus may spread mostly by
green peach aphids.
 Can render the ears unmarketable.

6. Control
Nature:
lady beetles
lacewing
pirate bugs
}not adequate control
Insecticide: such spinosad.

7. Corn root worm
Diabrotica virgifera

8. Taxonomy
• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Insecta
• Order: Coleoptera
• Family: Chrysomelidae
• Subfamily: Galerucinae
• Tribe: Luperini
• Genus: Diabrotica
• Species: virgifera

9. Description
 White and slender
 About 0.5 inch long when fully grown
 Brown heads
 Dark plate on the top side of their tails

10. Description
 Southern adult
 Yellow to green in color with a black stripe
along the sides of their wing covers
 About 7.5 mm long.
 Male wing covers are often nearly entirely
black or at least darker in pigmentation
 Female, which usually appears as more regular
stripes.
 Slight variations in these color patterns may
occur.
 Female adults have larger abdomens than the
males.

11. Description
 Northern adult
 Tan to pale green beetle about 6 mm long.
 Newly emerged beetles are usually cream or
light brown in color, but gradually turn green with
age.
 No marked differences in coloration exist
between sexes, but female beetles with their
longer and larger abdomens are typically larger
than the males

12. Symptom
 Rootworm larvae
chew the aerial roots
of maize stalks
 Penetrate the damage
root and gain access
to the inner stalk.
 Maize stalks prone to
tipping
 Damaged root served
as 2nd infection
 Severe root damage
result in lodging of
corn plants

13. Control
 Early planting
 Crop rotation
 Insecticide
 Lorsban 15G
Insecticide
 Lorsban Advanced
Insecticide
 Chlorpyrifos

14. Armyworm
Spodoptera frugiperda

15. Taxonomy s
 Kingdom : Animalia
 Phylum : Arthropoda
 Class: Insecta
 Order : Lepidoptera
 Family : Noctuidae
 Genus : Spodoptera
 Species : frugiperda

16. Description
 Their name is from their behavior moving
army-like fashion
 They migrate as an army to new host plant..
 They feed primarily on grass such as oats,
wheat, barley and forage grasses.
 But due to hunger stress, they can be a pest
to other plants such maize, radish and sweet
potato.
 Have 4 stages of growth.

17. Egg
 Egg are usually round shaped
 0.75 to 1 mm size in diameter
 Shiny and smooth on egg surface
 Flat on the lower surface
 Bluntly pointed at the top
 Have sculpturing, lines and ridges on the surface
 Lay about 100-300 of eggs
 Egg hatches in 1 to 2 weeks affect by
temperature
 Greenish-white in colour.

18. Larvae
 Pale green in colour
 Mature larvae basically yellowish
or brownish-green with greenish
-brown head mottled.
 Hairless body mark with three
dark longitudinal stripes.
 Full grown are 30-35 mm long.
 Active at night feeding on
tender leaf tissue.

19. Pupa
 Brown, reddish-brown or black
 13 to 22 mm long
 The antennae, wing pads and
legs are firmly joined together.
 Abdomen free to twist around
if disturbed.
 At the tip of abdomen have a
pairs of hook
 Live in the soil under debris.
 Stage duration is up from 7 to
14 days in summer.

20. Adult
 Are light reddish brown moths
with wingspan measuring about 4 cm.
 The forewing is pointed with white
spot at the center.
 The hind wing are grayish and
more lighter.
 Adults are nocturnal.
 Active during the evening, feeding on
nectar, mating and searching for
oviposition side.
 Eggs are deposited in a row or cluster
at the base of plants.

21. Symptom
 Consume leaf tissue of
maize plant.
 Chewing the leaves, strip the
entire plant, and leaving only
the midribs of the plant.
 Move up the plant to feed on
panicles and flower.
 Larvae will feed on the flag leaves,
kernels and stems.
 Also eat the center of the young
stalk and destroy the plants.

22. Ways of control
 Scouting procedure (identify hot spots)- the best
time to scout is at night or dawn.
 Insecticide technique based on the group size.
 Use BT (Bacillus thruingiensis)- a product that
contain toxin that derived from bacterium.

23. Cutworms
Agrotis ipsilon

24. Taxonomy
 Common name: Black cutworm
 Kingdom: Animalia
 Phylum: Arthropoda
 Class: Insecta
 Order: Lepidoptera
 Family: Noctuidae
 Genus: Agrotis
 Species: Agrotis ipsilon

25. Descriptions
 Eggs
 Flattened on top
 White to dull or off-white in color
 Ribbed
 Eggs may be deposited on crop foliage
 Frequently found on weeds

26. Descriptions
 Larvae
 Fully grown larvae range from 1 to 1.75 inches in
length
 Commonly curl into a C-shape when disturbed

27. Descriptions
 Adult
 Pale brown forewings with dark brown, black
markings
 Translucent hindwings, greyish white with brown
venation hindwings have a thin dark line along the
margins of the hindwings
 Approximately 1 inch long with a wing span of 1.25
to 2 inches

28. Symtomps
 Attack seedlings
 Cut seedlings at the base
1. Active eater at night
2. Hide under debris on the soil surface during morning
3. Climb into the host plant to feed

29. Control
 Spray of insecticide:
 Ambush
 Pounce
 Sevin

30. Japanese Beetle
Popillia japonica

31. Taxonomy
 Common name: Japanese beetle
 Kingdom: Animalia
 Phylum: Arthropoda
 Class: Insecta
 Order: Coleoptera
 Family: Scarabaeidae
 Genus: Popillia
 Species: Japonica

32. Descriptions
 About 0.6 inch long
 0.4 inch wide
 Iridescent copper-colored elytra
 Green thorax and head
 Clumsy flier, dropping several centimeters when it
hits a wall

33. Symptoms
 Attack leaf and fruits
 Skeletonizing the foliage
 Consuming only the leaf material between the
veins
 May feed on fruit on the plants if present.

34. Control
 Soil insecticide (short term control)
 Traps (large quantity)
 Soap water spray mixture
} small amount pest
 Shaking a plant in morning

35. Grasshopper
Melanoplus differentialis

36. Taxonomy
 Common name: Differential grasshopper
 Kingdom: Animalia
 Phylum: Arthropoda
 Class: Insecta
 Order: Orthoptera
 Family: Acrididae
 Subfamily: Melanoplinae
 Genus: Melanoplus
 Species: differentialis

37. Description
 Adult males grow to 28–37 mm
 Females grow to 34–50 mm
 Brownish or greenish and as they age the color
will darken
 Male has boot-like appendages at the end of its
abdominal tip
 Inverted chevrons along the hind femur
 Hind part the tibia is yellowish with black spikes
 Adults tarsi are yellow along with its antennae

38. Symptoms
 Kernels in the ear tips, plus along the side of the
ear were consumed or heavily scared
 Exposed eated kernels
 Complete kernel removal
 Clip silks (hot & dry conditions)

39. Control
 Sprays of insecticide
 Addition of canola oil to insecticide sprays
 Improve control by making treated foliage more
attractive
 Baits containing carbaryl (Sevin) can be used.
 It would be more effective when the baits are
mixed with some insecticide and bran or some
other carrier and kill the grasshoppers that feed
on that bait.