Ent-506-2 Insect Pests of Maize and Sorghum.pdf

Maize and sorghum, both belonging to the grass family Poaceae, are vital cereal crops grown worldwide. Unfortunately, they are susceptible to a variety of pests that can significantly reduce yield. These pests can be broadly categorized into insects, diseases, and weeds.

Insects:

Insects are some of the most common pests of maize and sorghum. Here are some of the major insect pests:

Fall Armyworm (Spodoptera frugiperda):This highly destructive caterpillar feeds on the leaves and stalks of maize and sorghum, causing significant yield losses. It is native to the Americas but has spread to Africa and Asia in recent years.Maize Stem Borer (Busseola fusca):This moth larva tunnels into the stems of maize and sorghum, weakening the plants and reducing grain production. It is a major pest in Africa.Sorghum Shoot Fly (Atherigona soccata):The maggot of this fly feeds on the growing point of sorghum seedlings, killing or stunting the plants. It is a major pest in Asia and Africa.Sorghum Midge (Contarinia sorghicola):This tiny fly lays eggs in the developing sorghum flowers, damaging the seeds and reducing grain yield. It is a major pest in North America and Asia.Diseases:

Maize and sorghum are also susceptible to a number of fungal, bacterial, and viral diseases. Some of the most important diseases include:

Maize Lethal Necrosis Disease (MLND):This devastating viral disease can cause complete crop failure in maize. It is transmitted by thrips and is a major threat to food security in AfricaNorthern Corn Leaf Blight (Exserohilum turcicum):This fungal disease causes large, dead lesions on maize leaves, reducing photosynthesis and grain yield. It is a major disease in North America and Europe..Sorghum Grain Mold (Fusarium spp.):This fungal disease infects sorghum kernels during grain development, producing mycotoxins that can be harmful to humans and animals. It is a major disease in all sorghum-growing regions.Weeds:

Weeds compete with maize and sorghum for water, nutrients, and sunlight, reducing crop yield. Some of the most common weeds affecting these crops include:

Pigweed (Amaranthus spp.):This fast-growing summer annual weed can quickly outcompete maize and sorghum seedlings.pen_spark
Johnsongrass (Sorghum halepense):This perennial grass is a close relative of sorghum and can be a difficult weed to control.Nutsedge (Cyperus spp.):These perennial weeds reproduce by tubers and can be very difficult to eradicate.By understanding the different types of pests that can attack maize and sorghum, farmers can develop integrated pest management (IPM) strategies to minimize crop losses. IPM strategies can include crop rotation, resistant varieties, biological control, and the judicious use of pesticides.

2. Insects of Maize and Sorghum
Sorghu
m
Maize

3. Stem borer
Chilo partellus, Pyralideae: Lepidoptera
Maize Jassid ( Leaf hopper)
Zygina spp. Cicadellidae: Homoptera
Sorghum Shoot Fly
(Atherigona soccata) Rondani, Diptera, Muscidae Fall armyworm
Spodoptera frugiperda
Order: Lepidoptera Family: Noctuidae

4. Stem borer
Chilo partellus, Pyralideae: Lepidoptera
Hosts: Maize, sorghum, Sudan grass, Sarkanda, Sugarcane
Identification:
Adult
•Moth’s appearance: brown in colour
•Length: average of 25 mm across the
spread wings
•Female moths are larger than the males.
•The moths are nocturnal and only live for a
period of three days no more.
•25-40% of young plants are destroyed
Front wings: double row of black spots
near outer margin
Hind wing: smoky

5. Eggs: Whitish and later on change to
orange yellow to black before hatching
Flat, oval and scale like in shape
eggs in batches on the under surface of leaves
near the midribs (bunches of 20 eggs)
Larva: Four longitudinal stripes on body of
full grown larva (20-25 mm long with black head)
Pupa: cylindrical, brownish yellow and turns
to reddish brown
Affected Plant Stages
All stages.
www.infonet-biovision.org
The female moth lays an average of 300-500
eggs.
Two thirds of the eggs are laid on the
upper surface of the leaf and the remainder on the
underside

6. Active Breeds: March-April to Sept.- Oct
Inactive period:
Rest of period ;Hibernates in stubbles, stalks or unshelled cobs as
larva Nov-Feb
Period of damage: April-August
http://agritech.tnau.ac.in

7. Damage:

•Newly hatched larva feed on leaves and leave behind holes
•Later on larva forms tunnels in the stem and kills the central shoot in
form of dead heart
•At ear formation, larva enters from its base and makes tunnel in
centre of cob and feeds on grain as well
•Red mining in the midrib
•Bore holes visible on the stem near the nodes.
•Tender folded leaves have parallel “shot hole”
•Affected parts of stem may show internally tunnelling of caterpillars
•No dead heart when plant is attacked at later stages

8. http://agritech.tnau.ac.in
www.infonet-biovision.org

9. Control:
Destroy the stubbles of maize and sorghum
Use of light traps
Collect and destroy the egg clusters
Chemicals
Cypermethrin, Deltamethrin, Carbofuran,
Carbosulfan, neem products
Trichogramma spp.
Cultural practices
•Crop Monitoring
•Crop sanitation: removal of stem, stubbles
•Intercropping and habitat management
(Cowpea)
•Trap crop:
•Sudan grass (Sorghum vulgare sudanense),
Napier grass (Pennisetum purpureum)

10. Biological control:
▪Egg parasitoid:
▪Trichogramma chilonis are egg parasitoid @ 25
cards/acre with 500 eggs per card
▪Apenteles flavipes and Stenobracon sp. are larval
parasatoid
▪Larval and pupal parasitoid: Isotima javensis
▪The spraying must be synchronized with the egg-laying
of these broods to obtain the maximum control of the
pest

11. Trichogramma
chilonis
Isotima javensisTelenomus beneficiens

12. Chemical control:
•Carbofuran 10-15kg/acre (Soil application followed by light
irrigation)
•Cartap 13-15kg/acre (Soil application followed by light
irrigation)
Chemical Control:
•Voliam Flexi ( Thiamethoxam + Chlorantraniliprole) 25
WG @ 80 ml
•Carbofuran 3G @ 8-10 kg per acre borers in maize and
sugarcane
•Cartap hydrochloride 4G @ 9 kg / Acre
•Chlorpyrifos 40 EC @ 600-850 ml / Acre

13. Maize Jassid ( Leaf hopper)
Zygina spp. Cicaldellidae: Homoptera
•Leaf feeding insect
•Major pest of Maize
•Widely distributed throughout
maize growing areas
Food: Maize and sorghum
Conditions: Poor growing conditions for the
crop, long intervals between harvests and
spells of hot, dry weather.
•Transmit diseases such as viral disease
•Maize leafhopper transmits wallaby ear virus in
maize.
www.dpi.qld.gov.au

14. Active period: March-Oct
Inactive period: Nov-March
Period of damage: march-April
Mode of Damage:
•Both adult and nymph feed on either side of leaves.
•Suck plant material
•Feeding leaves has white streak or whitish dots which dry
up that affect crop yield.
Control:
Nitenpyram, Flonicamide,
Deltaphos, Actara
Adult: Yellowish appearance, hind
wings bluish
Egg: light yellow green and turns to
yellow green
Nymph: 5 nymphal instar

15. Sorghum Shoot Fly
(Atherigona soccata) Rondani, Diptera, Muscidae
www.infonet-biovision.org
Alternative hosts: Maize, Finger millet, Bullrush millet, Rice, Wheat, Several species
of grasses

16. Identification:
Adult fly =4 mm
Looks like a small house fly
Head and thorax of female are pale grey
Abdomen is yellowish with paired brown patches
Male is more blackish

17. Damage:
Insects attacks on young crop.. In six leaf stage
•Eggs laid on underside of leaf
•Maggots bore in the base of young shoot
•Killing the growing point and youngest leaf
•Maggots crawl up and reach base of leaf blade to enter in shoot
•Leaf turns brown and withers to make dead heart
•Seldom attack after 6 leaf stage
•Tillers are produced in older plants and mature later than main
crop.
•Total loss of yield= approx. 60 %
Control
Resistant varieties
Seed treatment against
shoot fly

18. http://ethiopia.ipm-info.org/images/Atherigona%20soccata%20Damage
%20symptom.GIF
http://test1.icrisat.org/satrends/02jul/Shoot%20fly
%203.jpg
http://vasatwiki.icrisat.org/images/7/75/Sor1.jpe
g
Dead heart