Page 6 - National Poultry Newspaper

Litter beetle control
Vet’s
View
by ROD JENNER
THE litter beetle, also known as lesser meal- worm and black beetle, is a common insect pest of poultry farms Aus- tralia-wide.
It is capable of carrying and transmitting a number of diseases of significance to poultry and can cause considerable damage to insulation and cladding, leading to increased en- ergy costs and repair bills.
Chickens cannot digest the hard exoskeleton of the beetle, which, in high enough numbers, can physically obstruct the in- testinal tract and slow the passage of feed.
Life cycle
The life cycle of the lit- ter beetle ranges from five to eight weeks.
All life stages can be found in the litter of the
poultry houses.
Larvae hatch and grow
over a 40 to 60-day pe- riod, then burrow into the floor, ground or other suitable material (such as insulation) for seven to 12 days to pupate.
Litter beetles can de- velop large populations within poultry sheds.
A population of litter
beetles has been recorded to be as dense as 1000 beetles per square metre inside broiler houses.
Using the typical house size in Australia of 15m wide by 150m long, the total house population can be as large as 2.2 million. Biosecurity risk
Litter beetles are known vectors of a wide range of poultry pathogens, includ- ing Marek’s disease, IBD, NDV, AI, ILT, salmonella and campylobacter, and are able to transmit these pathogens over a wide range as they migrate from shed to shed.
Poultry readily con- sume both adult beetles and mealworms, thereby becoming infected with pathogens.
They can therefore play a vital role in the spread or carry-over of significant disease-causing agents. Control of litter beetle infestations
The control of litter bee- tle is based primarily on spraying insecticide dur- ing the cleanout process.
All currently available insecticides rely on direct contact with the insect, so the method of application is very important in order to achieve good success with chemicals.
Clay floors pose a par- ticular problem due to the burrowing activity of the pupating mealworm, which takes it out of reach of contact.
It’s important that an insecticide has some re- sidual activity so when the adult beetle emerges, there is still active chemi- cal present.
Historically, a number of classes of insecticides have been successful in eradication of infesta- tions, but resistance to chemicals is a common occurrence.
Resistance to feni- trothion and cyfluthrin in Australian populations
has been demonstrated and has led to the intro- duction of new-generation insecticides.
Preventing resistance
Management and pre- vention of resistance in litter beetle populations is a vital part of a successful control program.
Resistance arises through the overuse or misuse of an insecticide against a pest species and results in the selection of resistant forms of the pest and the consequent evolu- tion of populations resist- ant to that insecticide.
Insecticide resistance management strategies seek to minimise the se- lection for resistance to any one group of insec- ticide.
This requires an under- standing of insecticides because they are grouped according to similarity of mode of action in control- ling insects.
Mode of action refers to the biochemical pathways that are disrupted in the insect by exposure to the chemical.
Rotation of MOA groups
When choosing which insecticide to use, it is im- portant to look at the MoA group of the insecticide.
The MOA group is al- ways clearly stated on the label.
Resistance development occurs between chemicals within the same group, but not between MOA groups.
Prolonged use with a single MOA group will inevitably lead to the de- velopment of resistance to that group, rendering it ineffective.
In order to overcome this problem, rotation of chemicals between groups is very important.
This breaks the cycle of resistance development and returns the popula- tion of beetles back to a susceptible state.
Most of the insecticides registered for use against litter beetles fall in the MOA 3A group, with the exception being spinosad, which is a MOA Group 5 chemical.
An annual rotation with spinosad between batches of chickens is a very im- portant step in a long-term beetle management strat- egy.
Providing professional engineering services for the poultry industry
46 Anna St, Beaudesert QLD 07 5541 3500 acsengineers.com.au
Page 6 – National Poultry Newspaper, December 2018/January 2019
www.poultrynews.com.au