insects of grain

8/7/2019 INSECTS OF GRAIN

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PEST TYPEPEST TYPE

1.Commodity Feeders

Primary Pests or InternalFeeders

² Attack whole grains

² Larvae feed and developwithin the kernel

Secondary Pests orExternal Feeders

² Feed on grain dust and

broken kernels² Can not damage whole

grain

² Follow internal feeders,i.e. damaged grain

² Grain in poor condition,microbial activity.



2.Fungal Feeders

Fungal feeders are often present on ripenning grain and usually die out in storage

but may persist in poorly stored grain or in grain heavily infested with other

insects

3. redators

Many storage pests will prey on other insects present,including members of their

own species.Obligate predators only feed on other insects.

4. arasitoids

Parasitoids are beetles and moths.Larvae of them develop in or on their host

and killin it.These are potential ¶beneficial· insects as they can control pest

populations.

5. cavengers

Some scavengers species feed on bodies of insects and other dried material of

animal origin.Many are imporatant pests of stored products of animal origin such

as wool,hides,skins and dried fish.



Adults

Knowledge of the basic structure of beetles is required for their

identification.Terms illustrated below are used in the following species

descriptions.

Larvea

Larvae of beetles found in stored products have one of five distinct

body forms,which are described and illustrated below



A ODOU :Legless,immobileand lives internally within

foodstuff

CARABA IFORM: ffectivelyimmobile when mature,legs

partly or fully developed.Liveswithin foodstuff for all or all but

inital stage of life



CAM

OD ¡ IFORM: ¡ logate flattened bodywith well-developed legs,usually paleand translucent,head capsule and/or

last abdominal segment may bepigmented.Active,lives freely within

commodity

LA RFORM:Body is long andcylindirical,cuticle leathery,legs

relatively short.Active freelywithin commodity.



1.Cigarette BeetleLasioderma serricorne(Anobiidae,Anobiinae)

Identfcaton

Adults:3-4 m,brown,globular.Antenae long,segments saw-like,elytra smooth with fine

hairs.

Active,short-lived do not feed on

Larvae:Scarabaeiform,legs fully developed. mature.

¢ imilar species:Stegobium

£ est type:Primary pest,secondary pest

Commodities attaced:Dried material of anmimal and vegetable origin,especially

tobacco,nuts,herbs and spices,seeds,grain and grain products

¤

conomic importance: High in artifacts and processed goods,minor in raw

cereals.Important

pest of herbaria and museums

Life cycle:Optimum-26days at 30·C,70%r.h.

Maximum population growth rate per month-20.



2.Drugstore BeetleStegobium paniceum (Anobiidae,anobiinae)

Identification

Adults:3-4

mm,brown,globular,last three segments of antennae form looseclub ,elytra with fine

Longitudina ridges and fine hairs. Active short-lived do not feed on commodity,fly

Lavrae:Scarabaeiform,legs fully developed internal feeders,immobile when mature.

¥ ggs;laid in crevices in commodity.

¦ imilar species:Lasioderma

§ est type: Primary pest,secondary pest

Commodities attacked:Dried material of animal and vegetable origin,especially nuts,herbs and

spices,seeds,grain and grain products

¥ conomic importance:High in artifacts and processsed goods,minor in raw cereals.Important pest

of herbaria and museums

Life cycle:Optimum 40days at 30·C,60-90% r.h.




3.Spider Beetles(Anobiidae,Ptininae)

Identififcation:

Adults:2-5 mm,long-legged,globular,resemble small spider.Some species hairy,others

totally or partly shinny.Antennae long and hair-like.long-lived,feed on commodity,some species can

fly

Larvae:Scarabaeiform,legs fully developed. internal feeders.immobile when mature

̈ ggs-laid in crevices in commodity.

© imilar species:none

est type:Secondary pest,scavenger

Commodities attacked:dried material of animal and vegetable originUsually infests aged residues

̈ conumic importance:generally low except under cool temperate conditions

Distribution:worldwide,especially in temperate regions,tolerant of cold conditions

Life cycle(P tinus ocellus) Optimum-61 days at 27·C.




4.Cocoa Weevil,Coffee-Bean Weevil Araecerus fasciculatus(Anthribiidae)

Identification

Adults: 3-5mm,globular,long legs and antenae,elytra patternet with light and dark patches giving

chequered appearance.last three segments of antennae form loose club.-on emergence leave neat

exit hole,short lived,do not feed on commodity,fly

Larvae: Scarabaaieform,legs partly developed-on hatching bore into commodity,development

Completed inside sinfle seed.

ggs: laid onto seed or root

imilar species: bruchhids(9-14)

est type :Primary pest

Commodities attacked :Cocoa,coffee,dried cassava and yams,maize,groundnuts,brazil

nuts,nutmegs

conomic importance :High on high value crops,low elsewhere

Life cycle :Optimum 22-66 days at 28-32·C,>60% r.h.

Maximum population growth rate per month -40.



5.Larger Gran BorerP rostephanus truncatus(Bostrichidae)

Identification:

Adults: 4mmiblack,cylindirical in cross section.Head bent downwards,concealed.Tip of abdomen

square,boundary between end and side of elytra marked with ridge.longlived,feed and bore into

commondity,fly

Larvae: Scarabaeiform,legs fully developed-internal feeders producing lots of

flour,immobile when mature.

gss: laid on commondity or in tunnels bored bye adults

imilar species: Dinoderus(5),Rhyzoper ta(7 )

Pest type:Primary pest

conomic importance:High,especially in bagged and traditionally stored produce under subsistence

conditions.Pest of international quarantine concern

Commodities attacked: maize,especially on cob,and dired cassava.Often infests prior to harvest

Life cycle: Optimum : 26 days at 30·C,75% r.h.

Maximum population growth rate per month :25.



6.Rce WeevilSitophilus oryzae(Curculionidae)

Adult can fly.

Infest grain in the field

Adult weevil and grub (larvae) feed on whole grain.

Adult drills whole in grain and then deposits egg.

Primary pest

Requires grain moisture > 12%.

Small pits/punctures on surface of thorax

Two light colored spots on each wing cover

Life cycle Spots requires 28 or

more days.

Female can lay up to 300 or 400 eggs.

Females can live up to 4 or 5 months.

1/8 inch



7.Lesser Gran BorerRhyzoper tha dominica (Bostrichiedaei)

Identification

Adults:3mm,dark reddish-brown,cylindrical in cross section.Head bent downwards and

concealed.Tip of addomen tapered,end of elytra curved gradually. longlive,feed and bore into

comodity,fly

Larvae:Scarabaeiform,legs fully developed-internal feeders producing lots of

flour immobile when mature

ggs:Laid on commodity or in tunnels bored by adults.

imilar species: Dinoderus(6),P rostephanus(7 )

Pest

ype: Primary Pest

Coomodities attacked: Cereal grains,especially wheat,barley rice and sorghum(milo)

conomic importance :High,even in modern bulk storage systems

Life cycle :Optimum:25days at 34·C,70% r.h.

Maximum population growth rate per month:20.



Stored grain insects may also be controlled by:

1. Cooling stored grain through aeration

2. Treating grain with an insecticide powder or liquid residual chemicals

3. Treating infested grain with dichlorvos

4. Fumigating grain with phosphine or methyl bromide

5. Controlled atmosphere such as carbon dioxide in a gas-tight silo

6. Treating storage areas and equipment with residual chemicals such as

cypermethrin to kill off any remaining beetles.

7. Rice weevils in all stages of development can be killed by freezinginfected food below 0 degrees Fahrenheit for a period of three days, or

heating to 140 degrees Fahrenheit for a period of 15 minutes.



Applied as grain is being augured into grain bin.

Recommended Insecticides

² Storicide II: rice, wheat, grain sorghum, oats

² Actellic: corn and grain sorghum

High temperatures and high moisture content

will shorten residual life of protectant insecticide.

Do not apply grain protectant before high

temperature drying.

insects of grain

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