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Essay: Entomology: Understanding Cutworms and How to Manage Them

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ay  ASSIGNMENT#1

   “ENTOMOLOGY”

TOPIC : CUT WORM

SUBMITTED TO :

   SIR MUBASHAR

SUBMITTED BY:

    16120814-019

SR NO CONTENTS

1  CUT WORMS

2 INTRODUCTION

3 LIFE CYCLE

4  EXAMINE TEST FOR PEST

5 COMMON HOST

 6   DAMAGE SYMPTOMS

7 DAMAGE MECHANISM

8   DAMAGE EFFECT

9   MANAGEMENT

    1-CULTURALCONTROL

    2-BIOLOGICALCONTROL

    3-CHEMICAL CONTROL

10 REFRENCES

Cutworms ;

 Moth larvae  hide under litter during the day time, coming out in the night for ffeding they are active at night. A larva  attacks the first part of the plant , namely the stem, often of a seedling, and consequently cuts it down  and damage it; hence the name cutworm. Cutworms are not worms, biologically speaking, but  are caterpillars because they cut the plant and damage them-

   

  Figure 1;cutworm larva

  The cutworm larva of the Large Yellow Underwing (Noctua pronuba)

Agrotis species – Cutworms;

TAXONOMY;

Phylum: Arthropoda

Class: Hexapoda (Insecta)

Order: Lepidoptera

 Family: Noctuidae

 Genus: Agrotis

Description:

1-Many species of  cutworms that are all similar in appearance.

2- larvae of all species grow to about 40-50 mm long –

3-Are relatively hairless, with a distinctly plump-

4-Greasy appearance

5- Dark head.

 

    Figure 2;CUT WORM LARVAE

Common names:

Blackorgreasycutworm,variegatedcutworm.

Latin names:

 Various Agrotis spp. Including

 Agrotis ipsilon (Black cutworm)

Agrotis longidentifera (Brown Cutworm)

 Agrotis segetum (Common Cutworm)

 Agrotis subalba (Grey Cutworm)

 Also Peridroma saucia, Chorizagrotis auxiliaries amongst other species.

Life Cycle;

Female moths can lay  eggs singly or in small clusters of eggs.  Femake moth   deposit them on  the surface of low-growing plants and on plant residue.  Migrating moths lay eggs mostly on the soil- And the larvae  feed on plants part.  Young larvae feed on the leaf or crops  until their length  increases about 1/2 inch .  Newly growing   weeds can be very attractive sites for egg laying and  for feeding . At this stage, they can start  feeding on seedling stems, either cutting them or burrowing into stem.  Corn, peppers, tomatoes, beans, and the crucifer family are common hosts, but they will attack different kinds of herbaceous plants.

Cutworm grow as large as two inches approximately .  Their  generations is mostly 3 per year.  Native cutworms  in weedy areas or pastures.  It is  in these areas and along field where problems occurs.

 If weeds  grow in the fall after crop harvest and the fall and winter conditions are mild,  large numbers of cutworms may   survive  to attack vegetables in the spring.

Cutworm abundance , development and survival  is  affected by weather,  humidity especially  by rainfall.   Moths mate and lay eggs from  spring to late summer/fall –

Adult stage:

Dark gray, black or brown colored moth- They have  markings on their front wings-

 Moth wingspan of  about 40 to 50mm-

 Moth Length from  20 to 30mm.

Females are darker  in colour than males –They start egg laying 5 to 11 days after  Their emergence.

 Moths adults are mostly  nocturnal –They lay eggs on vegetation, on moist ground places. During the daytime light, adults hide in vegetation or under leaf-

  Egg stage:

Pearly white colour, round in shape, diameter of 0.5mm. Eggs are laid singular or  clusters of eggs. Eggs may be clusters of up to 2000eggs. Eggs hatch during the 3 to 11 day stage, but it mostly depends on temperature condition-

Larvae stage:

Larvae are greasy in appearance and can have color from gray to brown or black depending on species type. Larvae  have two spotted yellow stripes running along the back on the body. In moth are 6 larval instar stages. Larvae length  may reach up to to 50mm when development occur at mature stage but at hatching time larval length is 6mm. Generally hide in the soil or in different places during the light of daytime. They can overwinter and continue feeding for up to 20 weeks, depending on food availability-

Pupa stage:

Are shiny, brown in colour and smooth surface-And about 20mm in length. Cutworms can overwinter as pupae, which are found mostly under the soil surface.

   

   Figure 3;CUTWORM LIFECYCLE

LIFE CYCLE OF POTATO CUTWORM;

   

    Figure 4;Life cycle of potato cutworm

Confirmation TEST OF PEST;

 soil around damaged  plants  reveal cutworm larvae. when larvae disturb they change their shape became curly and gain c shape . May remain motionless for a short period of time-

Damage to foliar tissue  occur by other defoliating insect pests such as armyworm and grasshoppers.

• Adult moths lay hundred of eggs and their preferr site  for this purpose is moist soil or poor growing weeds –

• Temperature help in producing more generations and number of cutworm increases. Up to four generations may produce during the reproductive season depending on species –

COMMON HOST FOR CUTWORM:

Cutworms are polyphagous –They have  different  variety of host , including different vegetables and cereal crops such as asparagus, bean, beet, cabbage, castor bean, cotton, grape, peanut, pepper, potato, radish, spinach, strawberry, tobacco, rice, rye and tomato

HOST LIFE STAGE EFFECTED:

Seedlings and young plants are mostly effected by cutworm-

DAMAGE SYMPTOMS:

Cutworms particularly feed at night -cutworm   they are nocturnal-larvae feed on weeds, and  plants if  available, leaving  irregular holes in the leaves and burrowing in their stem. Such early feeding by larvae  is of little importance to plants.

Larger larvae completely cut  stalks, which can cause plants to wilt ,and in this way destroy the plants  completely -They sometimes drag cut plants under soil clods in the soil  and in this way they may attain their feeding during the daylight hours.And in this way they feeding occur during day light-

In some crops like potatoes and  vegetables, damage appear as unsightly holes in the subterranean tubers and because of this secondary funji may attack the plants-

When cutwormsre numerous  in number  and their attack occur they   can destroy as much as 75% of a crop and loss of farmers occur-

    

  Figure 5;cutworm leaves

Geographical distribution OF CUTWORM:

Worldwide distribution of these worms-they found all over the world-

Mechanism of damage:

Cutworms ‘cut’ the stem of plants , thus killing the plant and destroying the crops. In some situation replanting may be necessaror  for obtaining  crops. larger cutworms consume or eat foliar material and burrow into the stem of plant as a result wilting in plants. Most cutworm feeding takes place at night because they are mostly nocturnal. Some  feeding may occur during the daytime, but cutworms  remain  below the ground at day time.

 

Damage to stems Black cutworm damage

in the field

Crops attacked;

All field crops, including cereals, pulses, oilseeds and pastures may be attacked by cutworms-Cutworm destroy these crops by cutting leaves-

DAMAGE EFFECTS: Young seedlings are mostly  affected by cutworm damage . larger plants are less affected by  cutworm attack but damage may be severe if cutworms burrow into the stems of plant-

 

  Figure 6;cutworm damage on potato

• Cutworm  should be noticed using adult moth traps light or pheromone at the onset of the growing season to estimate intensity of infestation.

• Economic damage DUE TO MOTH:

 Replanting may be necessary if the crop  is more damaged by cutworm feeding. Damage is most severe when a large number of cutworm larvae are present at plant growth time. one larva can destroy or eat  up to 4 plants. Yield loss as high as  may be up to 47%  due to cutworm attack-

Dealing with Infestations

• The presence of many birds feeding in the field may show cutworms  are present-

• Beneficial nematodes released in moist, spring soil will attack and destroy cutworms living underground.

• At the first sign of moths, release trichogramma wasps weekly for three consecutive weeks to parasitize cutworm eggs.

• Scattering  of diatomaceous earth around the  plants gives  a barrier to  cutworm larvae. Diatomaceous earth, the fossilized,  remains of prehistoric sea life-

• Spread  corn meal mixed with Monterey Bt  and molasses on the soil surface to attract and kill caterpillars. Eco-Bran will  kill caterpillars that feed on plant-

Management ;

Cultural control

• Plowing fields 3 to 6 weeks before planting will reduce risk of cutworm attack, by removing  hosts and by  disturbing  or destroying  eggs  of moths and overwintering pupae and larvae in the soil can reduce the chance of moth attack-

• At the end of growth season Plowing under residue  will reduce moths laying eggs on weeds in field and in thisway field prevented from moth-

• weed-free fields following crop emergenace reduces risk of cutworm infection-field should be weed free-.

Biological control;

• some natural enemies of cutworm present  including  different parasitic wasps, grasshoppers, viruses, and fungal pathogens.

Chemical control;

• insecticides must be applied in severe conditions for preventing growth of cutworm. Insecticide should be applied at start when damage is at the early stages  the infection should be  control at starting point– when  only 3 to 10% of total crop is damaged by cutting of cutworms. presence of cutworms detected by using a flashlight at night to monitor cutworm presence and damage due to cutworm-

Examples of common insecticides that are effective against cutworms.

Common name Residual* Notes

Carbaryl Medium Contact

Cyfluthrin medium-long Contact

permethrin medium-long Contact

REFRENCES;

1-http://maizedoctor.org/cutworm-extended-information

2-http://cesaraustralia.com/sustainable-agriculture/pestnotes/insect/Cutworm

3-https://www.extension.umn.edu/garden/insects/find/cutworms-in-home-gardens/

4-https://www.planetnatural.com/pest-problem-solver/garden-pests/cutworm-con

5-http://keys.lucidcentral.org/keys/v3/eafrinet/maize_pests/key/maize_pests/Media/Html/Agrotis species_Cutworms.htm

6-https://www.extension.umn.edu/garden/insects/find/cutworms-in-home-gardens/

in here…

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