Biological control of white grubs

Content

• Enemy species• Most occurring white grubs in Belgium and the Netherlands• Biological control possibilities• Chemical control possibilities• Working of nematodes• Life cycle:

– Garden Chafer– Welsh Chafer– Black vine weevil – others

• Determination

12 May 2011

Enemy species

Lawns and sports fields– Emelts = larvae of crane flies (Tipula)– Click beetles = larvae of wireworms – White grubs = larvae of beetles

(Coleoptera: Scarabaeidae = scarab beetles)

Perennials and shrubs– Othiorynchus sulcatus = Black vine weevil

12 May 2011

12 april 2023

Emelts

12 april 2023

Click beetles Bron:www.zin.ru

12 april 2023

White grub

12 april 2023

Larva Black vine weevil

Most occurring white grubs in Belgium and the Netherlands

• Hoplia philanthus = Welsh Chafer

(lawns, moist until drier sandy soils)

• Phyllopertha horticola = Garden Chafer (lawns)

• Amphimallon solstitiale = Summer Chafer

(lawns, dry sandy soils)

• Melolontha melolontha = Cockchafer (very local)

12 May 2011

Most occurring white grubs in Belgium

and the Netherlands (continued)

• Melolontha hippocastani = Chestnut Cockchafer (very

local)

• Serica brunnea = Brown Chafer

• Polyphylla fullo = Pine Chafer

• Aphodius sp. = Dung Beetle

• Anomala sp.

12 May 2011

Biological control possibilities

• Emelts (Tipula) nematode Steinernema feltiae (bad to moderate action)

• Bacteria preparation

based on Bacillus thuringiensis var. israelensis

(no homologation in Belgium and the Netherlands)

12 May 2011

Biological control possibilities

• White grubs

B-Green (Heterorhabditis bacteriophora) as from 12 – 15°C

+++ Phyllopertha horticola ++ Aphodius contaminatus + Anomala dubia + Hoplia philanthus + Serica brunnea - Amphimallon solstitiale --- Melolontha melolontha

12 May 2011

Biological control possibilities

• White grubs (continued)

Steinernema scarabaei most effective also against Aphimallon and Melolontha

(not native in Europe and cannot be produced for the moment)

• Black vine weevil

Heterorhabditis-System (Heterorhabditis megidis) as from 12°C

12 May 2011

Chemical control possibilities

• Results are disappointing, better results when injected

• Chlorinated hydrocarbons (e.g. Lindaan), Temik (aldicarb) and Confidor (imidacloprid) are forbidden, with a Confidor injection the larvae stop feeding.

• Other carbofuran, chloorpyrifos, …..

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Working of nematodes

1. Nematode searches actively for a prey

– excrements

– cuticula

– respiration (CO2)

– temperature

2. Penetration through natural openings: mouth and anus

3. Movement to the intestinal canal and penetration

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Working of nematodes

4. Release of symbiotic bacterium

Steinernema: Xenorhabdus

Heterorhabditis: Photorhabdus

5. Bacterium releases toxin blood poisoning within 48h

6. Reproduction of the nematode in the cadaver

7. Thousands of new nematodes leave the cadaver to

search for new prey

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Life cycle of Garden Chafer (Phyllopertha horticola)

12 May 2011

Life cycle of Garden Chafer (Phyllopertha horticola) (continued)

• Beetles (adults) copulate during the first night of their life and then lay 85 % of the eggs in the neighbourhood of pupation. During the next 3 weeks in May and June during the ripening gluttony they fly in late morning (10 – 12h) and feed with leaves. Then they swarm out 3 to 4 km from the birth place to lay the other 15 % of the eggs. The larvae eat the roots of the grasses.

• Treatment period August-September before the larvae drain deeper.

12 May 2011

Life cycle of Welsh Chafer (Hoplia philanthus)

Source: PCS

Fecundity before the end of June Year 1

Year 1L1 AugustL2 September

Year 2: L3 as from April

Year 3: L3 until April

Pupation May Year 3

12 May 2011

Life cycle of Welsh Chafer (Hoplia philanthus) (continued)

• The life cycle is spread over 3 years and the total development takes about 24 months

• Year 1

– Adults (beetles) lay eggs

(25 to 40 per female end of June, flight radius 10 meters)

– Eggs hatch end of July, L1 white grubs in August

– As from September L2 white grubs

(These white grubs hide in the winter months deeper in the soil)

12 May 2011

Life cycle of Welsh Chafer (Hoplia philanthus) (continued)

• Year 2

As from April, May L3-larvae, year with the most damage

• Year 3

L3 white grubs colour in April and May completely white and pupate in May

• Treatment period in April and May on L3-larvae when the soil temperature contains 15°C.

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Control of Welsh Chafer (Hoplia philanthus)

12 May 2011

Black vine weevil (Othiorynchus sulcatus)

Fecundity before the end of May

Pupation around May

Larvae as from June

Source: PCS

12 May 2011

Black vine weevil (Othiorynchus sulcatus) (continued)

• Adults around the end of May damage leaves and lay eggs. Eggs come out and become larvae (white grubs), which eat the roots. Pupation occurs around the month of May.

• In protected crops the development stages overlap. 

• Treatment period at soil temperatures above 12 – 15°C– April-May: against pupating larvae

– August-September: against larvae which have just come out

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Others

• Summer Chafer: 2-year life cycle, fly in the evening

• Cockchafer: 3- or 4-year life cycle

• Brown Chafer: 2-year life cycle, treatment period April-July

• Pine Chafer: 3 to 4 years

12 May 2011

Determination

• Adults are often not detected which is the reason why identification is done with white grubs

• Running white grubs– Phyllopertha horticola– Anomala dubia

• Twisting white grubs– Hoplia philanthus (reddish dorsel hair = )– Melolontha melolontha– Amphimallon solstitiale– etc.

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Determination

12 May 2011

Garden Chafer larva (Phyllopertha horticola)

Determination

Garden Chafer larva

12 May 2011

Determination

Bron:www.zin.ru

Source: Paul Parey

Adult Garden Chafer

12 May 2011

Determination

Black vine weevil larva

12 May 2011

Determination

Black vine weevil adult

12 May 2011

Determination

Welsh Chafer larva (Hoplia philanthus)

12 May 2011

Determination

Welsh Chafer larve

12 May 2011

Determination

Source: Paul Parey

Source: Ingrid Altmann

Adult Welsh Chafer

12 May 2011

Determination

Summer Chafer (Amphimallon solstiale)

12 May 2011

Determination

Summer Chafer larve

12 May 2011

Determination

Source: Paul Parey

Source: entomart

Adult Summer Chafer

12 May 2011

Determination

12 May 2011

Cockchafer (Melolontha melolontha)

Determination

Cockchafer larve

12 May 2011

Determination

Adult Cockchafer

Source: Paul Parey

12 May 2011

Application

• Always use an entire packing

• Remove all filters from the spray equipment

• Use spray caps with a diameter of min. 0.8 mm

• Use a good stir installation or return

• Apply in the evening or on a cloudy day

• Sprinkle the soil before application

• Sprinkle after application with 2 to 5 liters per m² (depending on the tatch)

• Keep the soil moist during 4 weeks

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Dosage

• Heterorhabditis-System (Heterorhabditis megidis)– Preventive: 0.5 million nematodes/m²

– Curative: 1 million nematodes/m²

• B-Green (Heterorhabditis bacteriophora)– Curative: 0.5 million nematodes/m²

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Packing

• Heterorhabditis-System:– 50 million

– 200 million

• B-Green:– 50 million

– 500 million

12 May 2011