Showing posts with label biology. Show all posts
Showing posts with label biology. Show all posts

Tuesday, August 27, 2013

The Story of Booklice – Biology and Behaviour, Implications for Control

Following on from the story of biscuit beetle and other larder pests, booklice are also often found in larders. They are not, however, feeding on the food directly, they are feeding on microscopic fungi that grow on starchy foods or packaging.

  • Tiny pale cream to brown insects
  • Often mistaken for mites
  • Crawling. Do not fly.
  • Often found on books, paper/cardboard packaging, in starchy foods (e.g. flour)
  • Seen on larder shelves
  • Known as psocids (pronounced sosids)
  • Are often only noticed when numbers have become high.
Check and dispose of any contaminated foods.
Clean shelves and treat with NO Bugs Super.
Books etc. can have light spray but ensure they are dried completely before placing back on shelves.
Fumigators can be useful but will not deal with them on their own.
  • Feed on microscopic fungi that grow on paper/starchy materials
  • Fungi need humidity
Keeping books, food, packaging etc. dry prevents growth of moulds and booklice will die.
Ensure NO Bugs Super or any other wet spray has dried completely before re-filling shelves.
Use dehumidifier or improve ventilation in infested area for long term control.
  • Many species.
  • Need to be expert to tell them apart.
  • Usually spread on books and packaging or in starchy foods.
  • Common pest of food warehouses.
Keep larder shelves treated to prevent spread if infested product brought in. Also works for pantry moth, weevils, biscuit beetle, etc.)

Monday, August 26, 2013

The Story of Biscuit Beetle and other larder pests – Biology and Behaviour, Implications for Control

Dermestid beetle
There are several insect pests that are commonly found in home larders feeding on spilled foods or infesting foods inside the packaging. It is usually the larvae of the beetles and weevils that are found in dried foods such as flour, biscuits, cereals, rice and spices. But the adults will be seen collecting on the shelves and in the kitchen.

The control of these pests is generally the same, whichever species you have infesting your larder.

  • Species – Biscuit beetle, larder beetle, spider beetles, fur beetle, weevils, and more
  • Eat many dried products found in kitchen larders, and other materials made from animal and plants
  • Biscuit beetle and others bore holes into products and packaging similar to borer holes in timber
  • Biscuit beetle look very like borer beetles – related
  • Larvae do most damage in dried products
  • Female beetles lay eggs on product or packaging
  • Eggs hatch as larvae that burrow into product
  • After weeks-months larvae pupate and adult beetle bores its way out
  • More activity in summer months
Infested foodstuffs should be disposed of. Dried foods should be kept in sealed containers – glass jars, Tupperware, tins etc. Clean up spilled foods.
Cupboards can be sprayed with NO Bugs Super when empty. Leave to dry completely before putting foodstuffs back.
Feeding habits
  • Biscuit beetle eat starchy food – biscuits, grain, flour, pasta, cereals etc.
  • Fur beetle – leather, fur
  • Weevils – biscuits, grain, flour, pasta, cereals etc.
  • Spider beetles – biscuits, grain, flour, pasta, cereals etc.
  • Do not usually survive outdoors
  • Transported in foods or on packaging as beetles, larvae or eggs.
NO Bugs Super fly/spider treatment may help but prevention is best done by checking for any affected product before putting in pantry and storing in jars/Tupperware/tins etc.
Other pantry pests include pantry moth and booklice (see specific learning notes for these).
What do you call a gingerbread man with one leg?
Limp biscuit.

Tuesday, August 13, 2013

The Story of Bed Bugs – Biology and Behaviour, Implications for Control

  • Females can lay 200 eggs a year
  • Eggs hatch as nymph (tiny versions of adults) just visible to naked eye
  • 5 nymph stages (instars)
  • Need blood feed to move to next stage (instar)
  • Adults – size of apple pip
  • Only adults are sexually mature
  • Cycle as short as 5-6 weeks
Bed bugs can breed quickly. One pregnant adult can become thousands of biting nymphs and adults in a few months.
Early control, when numbers are low, is easiest. Development through many nymphal stages gives opportunity to break life cycle – Insect Growth Regulator (IGR) such as pyriproxyfen stops nymphs being able to moult and grown new chitin skin.

Hiding places
  • Flat body shape to fit in narrow spaces.
  • Cracks, crevices, seams, voids, skirting, under carpet edges, electric sockets, furniture, curtains, ………..
  • …..and, of course the bed.
  • High and low.
  • Usually within 5 metres of bed.
  • Adjacent rooms.
  • Smell when heavy infestation.
Hard to find. Need to be VERY thorough. Treat all possible hiding places, not just where insects are found. Spray with long lasting spray containing insecticide to kill adults and nymphs and IGR to break life cycle. Fumigator to get to places that are hard to find/treat.

Feeding habits and bites
  • Blood suckers – hypodermic proboscis
  • Feed on people and pets
  • Feed at night (usually ~2am)
  • Inject proteins – anaesthetic and anti-coagulant- don’t feel bite and to stop blood blocking proboscis
  • These proteins cause allergic reactions in some people (not all) causing red itchy swelling.
  • Bites are often made in a straight line as bug walks across skin.
  • Ankles, wrists, torso, legs and arms are most common bite sites.
  • Fill up like balloon with blood – flat translucent to round and dark red
  • Small drop of blood on end of proboscis leaves +like mark on bed linen.
  • Excreta like tick made with black Biro.
  • One feed can be enough to keep bug alive for months
  • No evidence of causing disease but very unpleasant
  • Not all bites or skin reactions are caused by bed bugs or other biting insects. Other environmental factors can cause similar reactions. Even thinking about fleas and bed bugs tends to cause psychological feeling of itchiness, scratching and skin reactions.
Treatment must be long lasting and continue past last sighting. No bites (reactions) may not mean no bed bugs.
Bed bug infestations can only be confirmed by finding bed bugs.

  • Bed bugs do not fly
  • Bed bugs will not crawl far from the bed of their host
  • May choose luggage, boxes, furniture etc. as hiding places and are carried with these items from place to place.
  • Increased world travel has made them more common again
  • Numbers dropped dramatically when powerful insecticides used (e.g. DDT). Now the powerful insecticides are banned so numbers have grown.
Travel and moving hose are common ways for bed bugs to spread. Treat luggage before travel. Check accommodation for evidence of bed bugs before staying.
Kiwicare products work but more effort is required than when using the like of DDT.

  • Just one that causes problems for people. – Cimex lectularius
  • Other species specific to other animals e.g. bat bed bugs
Safe products
  • US EPA approve product ingredients for use in bedrooms
  • Include permethin and pyriproxyfen in NO Bed Bugs and cyphenothin in NO Bugs Borafume.
Kiwicare NO Bed Bugs Box is safe to use in bedrooms. Can be used on beds but recommend only underside and seams of mattresses. Do not use on bed linen.
Bed linen and clothes can be put in hot wash, tumble dried on high heat or placed in freezer (24hrs) to kill bugs and eggs.

Have you heard about the lady pregnant bed bug? She gave birth in the spring.

Saturday, August 10, 2013

The Story of Ants – Biology and Behaviour, Implications for Control

I have recently been giving some talks on pests and diseases in the home and garden and how to solve problems.

I thought it might be useful to publish some of the notes from these talks. This first one is about ants. I have summarised the biology and behavior of ants and what the implications of these are on how to control infestations.

  • Flying ants (not all species) are ants mating
  • Queens and males mate in flight
  • After mating males die and queens fly to seek nest (not usually more than 100m from original nest)
  • Queen looses wings
  • Starts colony
Flying ants annoy people as there can be many thousands. Treatment is not usually effective and most of the ants will die within a day or two.

To prevent infestation it may be advisable to treat possible nest sites in area with spray (NO Bugs Super, NO Ants) and use granules (Ant Sand and Lawngard Prills).

Nest Site

  • Dry – rain could drown nest
  • Warm – insects are more active when warm
  • Sunny – radiant heat can make ground and ants warm even on days with cool air temp – micro-climate
  • Sandy soil – easy to dig out nest chambers, well draining
  • E.g. under concrete path, under rock etc.
  • Sometimes nest in building, but if so, it probably be in exterior wall or eaves on sunny side
Deny ants nest sites: Repair cracks in concrete, paths, walls, etc. Apply Ant Sand to cracks and edges of paths. Apply Lawngard Prills to soil areas (particularly flowerbeds and lawns close to house) water in.

Stop ants getting in; spray base of walls, doorways, windows and around vents, where pipes/cables etc. run through walls.

Building Colony

  • Queen lays eggs which hatch as sister workers (no males)
  • In early stages queen will forage for food
  • Then workers take over gathering food and queen just lays eggs
  • Workers tend eggs and maintain nest
  • Colony grows where there is food, nest site, warmth, low competition
Early control, when numbers are low, is easiest.


  • New queen/s produced in nest
  • New queen and a few workers start new nest
  • New nest genetically similar or the same as old nest – co-operation – same colony – super colony
  • NZ imported species spread from one or few original colonies – all genetically similar and will co-operate – may be one huge colony (super colony)
Important not to disturb nest (particularly one with multiple queens) as disturbance causes queens and workers to bud; heading off in different directions to set up new nests; he result being spread of the problem. I.e. do not spray nest site before baiting for ~2 weeks first. When spraying or using granules at nest site treat around nest entrance/s not in nest entrances.

It is likely that other nests are in the vicinity. Controlling/killing one nest is rarely enough to get rid of them permanently. Ants are likely to spread in again from a neighbouring nest/colony.

Multi-queen colonies/nests

  • Some species will have more than 1 queen in a nest (e.g. Argentine Ants, Darwin Ants)
  • Faster growth of numbers
  • Easily spread
  • Argentine ant queens forage
  • Very easily spread on cars, plant pots
  • 1 queen and 20 workers enough to found new nest/colony
If you have ants (particularly Argentine ants) spray plant pots, boxes, car undersides etc. before moving to other properties.

Numbers – Nest and colony

  • Thousands, tens of thousands, even hundreds of thousands in single nest
  • Super colony – many millions?
  • ~5-10% foraging workers – so what are seen is small part of colony
Killing all the workers (foragers) that are seen in a garden or house will not kill the colony. Nest can reproduce and replace 5-10% in a few days. Baits are most effective as the poison is taken back to the nest to kill at/in the nest. Use sprays and granules as barriers to nuisance trails.


  • Protein – insects, seeds…..
  • Needed for colony growth and producing larvae
  • Some species target other insects and invertebrates that compete with them for food; removing competition (Argentine ants when moving into new area, biodiversity threat)
Kiwicare Gel Bait contains liver protein.
  • Carbohydrate – sugars, plant material (fungal breakdown)…. 
  • Energy; needed when ants/nest very active
Gel and liquid baits contain sugars.
  • Farming
  • Some ants feed on honeydew (sugary fluid) excreted by sap sucking insects such as aphids, scale insects, mealy bugs.
  • Ants protect sap suckers from attack by predators in a mutualistic (benefits both) relationship
Control aphids, scale, mealy bugs on garden plants with Super Spectrum, Carbaryl etc. so that ants cannot feed from them.

  • Very little fats or oils – ‘healthy lifestyle?’
  • Scouts sent out from nest to search for food – pheromones in nest ‘tell’ scout what sort of food the nest needs; protein or carbohydrate
  • Find food and lay pheromone/chemical trail back to nest
  • Tells (by pheromone and behaviour) foraging workers to follow trail to food
  • Foraging workers follow trail like ‘robots’ and may walk past and ignore other food
  • Each time a forager returns with food it also adds to chemical trail, encouraging more workers to follow it to food
  • As food runs out trail diminishes and fewer workers follow it until it stops
  • Ants live in a ‘chemical world’ and can be attracted to or repelled by some chemicals including cleaners, insecticides etc.
Baits must be placed on clean places with no deterrent chemicals. Do not spray areas around baits. Use sprays as barriers.

Baits may be ignored for days when ants are feeding somewhere else or the colony needs a different food type. Do not move baits, even if they are not being fed on. But replace bait as it is eaten and if it gets dried hard.

  • Collected food fed to other workers, queens and larvae in nest that do not go foraging
  • Direct feeding – food carried by foragers and passed straight on to others
  • Regurgitation – food ingested and regurgitated to others
  • Anal secretion – food digested and honeydew like secretion for rear fed to others
  • Sterile eggs – food digested and sterile egg produced which is fed to others e.g. White Footed ant
  • Farming – food (plant and insects) infected with fungus – ants feed on fungus
For some ants (e.g. white footed ant) bait toxins are not easily passed on to others in a colony as the ant has ingested the poison and died, or the toxin is filtered out of production of anal secretion or sterile eggs.


  • Almost all species that are pests have come in from overseas (invasive).
Argentine ants – world’s worst invasive.
  • No smell when squashed
  • Trails like motorway; several ants wide
  • Small (2-3mm) brown to black (like Darwin and White footed)
  • Super colonies
Darwin ants
  • Smell when squashed
  • Trails single file
  • Small (2-3mm) brown to black (like Argentine and White footed)
  • Super colonies
White footed ants
  • Smell when squashed
  • Small (2-3mm) brown to black (like Darwin and Argentine) 
  • with lens it is possible to see pale ends of legs (feet)
  • Super colonies
Black house ants
  • Small (2-3mm) black
  • North island
  • Native garden ant
  • Larger (3-5mm) than above
  • Black
  • Smaller numbers in nests
Biosecurity Risk Ants – Not yet established in NZ

Identification of ant species can be important in knowing how to treat most effectively.

Colony Death

  • No queens – in super colony species a queen can be recruited from another nest
  • No food
  • Nest drowned out
  • Cold
A combination of control methods is almost always required to get rid of an ant infestation. Pro-active control each year is the best method.

Ants outside in the garden are rarely a problem, only when they trail indoors do they become a pest. Therefore, treat to keep ants outside and prevent their entry.

What is the world’s largest ant? The Eleph ant.