FAQs

GENERAL QUESTIONS

Who is eligible to order a kit?

Any school in Australia wishing to rear Helicoverpa in their classroom!

How many students does the kit cater for?

The kit caters for approximately 25 students allowing for 4 rearing cups per student plus extras for the honeypots.

When do I need to order a kit?

Please order your kits at least 2 weeks before your preferred delivery date.  The kits are posted by courier on Tuesdays and they typically take 1-2 days to arrive depending on your location.  We recommend starting the rearing process on a Thursday or Friday when the neonates have just hatched.

What do I do when I receive the kit?

Use the kit checklist in the Technical Manual to ensure you have all the necessary kit components.  Make sure you have watched the instructional video under the Process Outline section of the Caterpillar Classroom website and read the Technical Manual so you are familiar with the rearing process.   Try to start the rearing process as soon as the eggs have hatched into neonates (within 1-2 days of kit arrival).

Where can I go to get some teaching and learning ideas for using the kit in my classroom?

Visit our Classroom Applications page on the Caterpillar Classroom website.

Where can I go to get more information about Helicoverpa, agriculture, the cotton industry, biological control and IPM methods?

Please visit our useful links page under the Technical Info tab on the Caterpillar Classroom website.

How can I share the resources I have created for others to see and gain ideas?

We would love for you to post your ideas, observations, experiment results, photos and useful resources on our Caterpillar Classroom Facebook page (https://www.facebook.com/CaterpillarClassroom)

Are Helicoverpa dangerous to humans?

No. Helicoverpa armigera larvae are considered a major pest of Australian agricultural and horticultural crops, particularly grain legumes, summer grains and cotton.  Therefore, it is very important that they are contained within the classroom environment.  Moths should not be released to outside environments as they can lay eggs on nearby plants including your school vegetable garden.  The larvae that hatch from these eggs may damage your vegetables.

One of my students has eaten a Helicoverpa larva, pupa or moth – is this harmful and what should I do?

It is unlikely that consumption of Helicoverpa would cause a serious adverse reaction in humans but it is advised to seek medical advice as soon as possible if deemed necessary.

Which school terms are the most suitable for rearing Helicoverpa?

Terms 1 and 4 are the most suitable terms due to the warmer temperatures.  Terms 2 and 3 are less suitable for rearing Helicoverpa particularly in cool climates because it may take 8-12 weeks to complete the lifecycle and pupae may enter diapause (a period of suspended development). 

THE REARING PROCESS

How long will it take to complete one lifecycle of Helicoverpa?

The lifecycle of Helicoverpa armigera takes 4-6 weeks in summer from egg to adult (moth) and 8-12 weeks in spring or autumn.

What do I do if I need to delay the start of the rearing process?

If you are unable to transfer the neonates within 1-2 days after the kit arrives, keep the eggs/neonates in a cool area (above 9°C and below 15°C) for no more than 3 days.  Temperatures below 9°C may kill the eggs/neonates (NB: Conventional refrigerators usually run at temperatures between 4-6°C).  Store the bag of diet in the fridge until you are ready to use it.

What do I do if the eggs haven’t hatched when we want to start rearing?

If possible, hold-off until the eggs have hatched into neonates.  This ensures you have a live larva in each rearing cup.  If this is not possible you can transfer eggs into the rearing cups using the paintbrush provided. If your eggs have not hatched within a week after receiving the kit please contact us via the Contacts page on the Caterpillar Classroom website.

What hygiene is required when handling?

Always follow good scientific hygiene practices and always wash hands thoroughly before and after handling Helicoverpa eggs, larvae, pupae and moths.  Gloves can be worn if desired. 

Is the diet provided harmful to students?

DIET SHOULD NOT BE CONSUMED BY HUMANS.  Potential allergens in the diet include soy flour, wheat germ and yeast.  If a student inadvertently consumes some of the Helicoverpa diet it is advised to seek medical advice as soon as possible.

LARVAL REARING

How much diet is required in each rearing pot?

Cubes of diet the size of dice will be sufficient food for the larvae to survive on.  One larva will typically eat 2.4g of food in its lifetime.

Can I have more than one larva in a cell?

Yes, but as larvae get bigger they turn cannibalistic (eat each other) so you will usually end up with only one larva per cell anyway.  This is a natural behaviour that is observed in their natural environment.

What do I do if the larvae are crawling away before I have time to put them into the cells?

If larvae are very active you may have to put the lid on the egg container between each transfer.  You can also shake a small number of neonates (less than 20) onto a square paper towel per several students to make the transfer process quicker and easier.  If neonates do crawl out of the container and across the desk wipe the table down with a cloth.

Why do I have to pierce the lid of the rearing cups?

This is to ensure the larvae have oxygen to survive.  You can use a thumb tack, needle or Stanley knife to make holes or slits in the lids.

Do I have to give the larvae extra food as they grow?

Each rearing pot should have enough diet to rear the larvae through to pupae if you have placed diet around the size of dice in each cup.  One larva will typically eat around 2.4 g of food in its lifetime.   

Where can I keep any leftover diet and for how long?

Any surplus diet can be kept in the fridge for up to 7 days.

Do the larvae need someone to care for them over weekends? Can they be left at school?

Larvae can be left at school over weekends and do not need to be cared for during this time.  Make sure they are not in direct sunlight or in front of an air conditioner or heater.  Ensure they have sufficient diet to sustain them. If students wish to take them home, the rearing pots can be transported easily in egg cartons.

What if some of the larvae die in the rearing pots?

It is not uncommon for several larvae to die in each tray.  Hypothesise what might have been the cause of death (e.g. lack of oxygen, lack of food, disease, parasitoids, predators etc).  Dead larvae can be placed in the general waste or left in the rearing pots until it is time to collect the pupae and then disposed of.

What if a larva escapes from a rearing pot?

This is unlikely if lids are tightly secured on the pots.   If some larvae do escape or chew a hole in the lid do not worry.  If you can find the larva easily, you can either return it to the pot or put it into a new pot.  If you wish to dispose of the larva place it in the freezer overnight then place it in the general waste.

What temperature should I keep the larvae at?

Keep larvae trays in a spot in the classroom where the temperature is most consistent.  Temperatures below 9°C or above 38°C may cause larval death.

Do the larvae need sunlight?

It is best to keep the larvae where they are exposed to the natural light of the day but out of direct sunlight if you are experiencing warm temperatures (above 28-30°C)

Will other animals such as ants or geckos eat the larvae?

It is very unlikely with a securely fitted lid on the rearing pots.

How long after my neonates hatch will they turn into pupae?

It takes around 20 days from hatching to pupation if larvae are kept at 25°C.  Warmer temperatures will increase their speed of growth and speed up the onset of pupation; cooler temperatures will slow their growth and delay the onset of pupation.

PUPATION

How long will Helicoverpa remain in pupation?

Helicoverpa typically remain in pupation for 2 weeks in summer and up to 6 weeks in spring and autumn.  In winter, Helicoverpa may enter diapause (a state of suspended development) and remain in pupation until temperatures rise in spring.

How can I tell if a pupa is alive?

Use the featherlight forceps provided in the kit to gently pick up the pupa either side of its head - if it is alive its tail will wiggle.

MOTH EMERGENCE AND EGG LAYING

Do the moths need food to survive?

Yes.  You can make food for the moths in your classroom using honey and warm water.  Please watch the Instructional Video on the Process Outline page or download the Technical Manual for instructions on how to make the honey solution and the honeypot.

How long do moths live for and how many eggs will moths lay in their lifetime?

Moths live for around 10 days and can lay 1000 eggs in that time.

Do the moths need looking after over the weekend and do I need to collect eggs over the weekend?

Make sure the honey pot is filled up on Friday afternoon.  This should sustain the moths over the weekend.  If moths are laying eggs over the weekend, collect the nappy liner on Monday and replace with a new one.

What do I do if some moths escape?

Do not panic if some moths escape. If you have a net or container available, you can use it to capture the moth and return it to the bucket carefully.  If you are unable to catch the moth, do not worry.  It will not cause anyone harm. 

END OF THE LIFECYCLE

If the students wish to continue rearing Helicoverpa in the pots once the lifecycle ends, how do I rear a second generation?

You can reuse your rearing pots and lids by washing them in warm water and detergent.  Let them dry then place some plant material, vegetables or an alternative food source in each pot for the larvae to feed on.  Alternatively, you can order another kit which will have diet in it. 

What do I do with moths/eggs/larvae once we’ve finished observing their lifecycles?

The easiest and most humane way to dispose of Helicoverpa is to place them in a container in the freezer overnight.  The frozen specimens can be used for further observations using a microscope or hand lens.  Once you have finished with them they can be disposed of in the general waste.

 

VIRUS VIALS

What do our virus vials contain?

Our virus vials contain approximately 25 mL of nucleopolyhedrovirus (NPV).  NPV is a very specific virus that infects and kills Helicoverpa armigera and Helicoverpa punctigera larvae.  It is harmless to all other insects and has no impact on humans. In Australia it is used in agricultural and horticultural crops to control H. armigera and H.punctigera caterpillars that damage grains, legumes, pastures, and fruit and vegetables crops.  For more information on NPV please visit:

http://www.daff.qld.gov.au/plants/field-crops-and-pastures/broadacre-field-crops/integrated-pest-management/a-z-of-predators,-parasites-and-pathogens/npv

http://www.daff.qld.gov.au/__data/assets/pdf_file/0007/76876/Insects-NPV-to-mange-helicoverpa.pdf

Information about commercial NPV products can be found at:

www.agbitech.com

What do I do with the virus vial?

Dilute the virus to make a virus solution that can be fed to caterpillars that are 3rd instar or younger (< 13mm in length).  You can observe the progression of virus-induced symptoms in the caterpillar over several days until the caterpillar eventually liquefies and dies.  

How do I make a virus solution?

Use the provided dispensing apparatus to dilute the required amount of virus (see below) in 1 L of good quality water (make sure the water is clear and has pH < 8).  Mix the virus and water well.  Using the provided dispensing apparatus, inject approximately 0.2 mL of the virus solution into each rearing pot - just enough to cover the surface of the diet but not so much that the caterpillar will drown.  A 1 L virus solution will be more than enough to kill thousands of caterpillars. 

What concentration of virus do I need to kill my caterpillars?

This depends on the size of the caterpillars when you infect them, your growing conditions (temperature) and how quickly you would like to kill them.  As a general guideline:

  • 1st-3rd instar larvae (1-13 mm in length) require 1 mL virus/1 L water.  The larvae will die in 6-8 days.  For faster speed of kill and if temperatures are below 25°C use 2 mL virus/1 L water. 
  • 4th-5th instar larvae (14-30 mm in length) are not always susceptible to death from NPV.  However, if you would like to experiment with killing these larger larvae use 3-4 mL virus/1L water.
What do I do once my caterpillars have died from virus?

The ooze that is generated from the dead caterpillar will be laden with virus particles.  You can put other caterpillars in the rearing pot for them to feed on the virus and then observe them die from the virus as well (this is called secondary infection).  The virus can also be stored for long periods in the fridge or freezer and used to infect other caterpillars or diluted with water and sprayed on the school or home vegetable garden if Helicoverpa larvae are present.  If you have no use for the virus generated from the dead caterpillars it can be disposed of in the general rubbish.

What do I do with unused virus?

You can store it in the refrigerator or freezer for several years until you are ready to use it.  It can be diluted and sprayed on the school or home vegetable garden to control Helicoverpa larvae.  Alternatively, it can be disposed of in the general rubbish.

Caterpillar Classroom is a practical resource to help foster education in biological and agricultural science, proudly provided by

AgBiTech

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