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Natural Pyrethrum makes a comeback

After years of shortages, natural pyrethrum is back in favour with smart growers.  With good reason. It works!

  • It kills any insect that you contact with a droplet, 
  • There is no residue beyond a few hours so it has only a 1-day withholding period
  • there is no special protective clothing needed during application
  • re-entry into the crop is simultaneous with the settling of the last droplet
  • it is impossible to build up to chronic symptoms
  • It is compatible with foliar fungicides and fertilisers

All these benefits yet a 1000 litre tank costs only $146 to fill. How far will 1000 litres go on your crop?Perhaps because of the complexity of the molecule and also because of the combination with the synergist piperonyl butoxide, natural pyrethrum does not seem to be challenged by resistance like most other insecticides.



A tomato grower at Bangalow on the NSW North Coast had so much trouble with whitefly he was almost considering turning his ‘igloo’ into a machinery shed. He’d pulled out a couple of rows of tomatoes and the ones still struggling were about half the size (bush and fruit) of those growing outside just 20 metres away. About $50 worth of Py-Bo turned the situation around.

A linseed crop on the Darling downs was under stress from lack of rain and consequently the heliothis caterpillars were devouring around 5% of what heads were left overnight. For under $20/ha he was able to eliminate the pests within an hour or so and get a harvest instead of ploughing it in.

Heliothis, monoleptas and loopers were all attacking a crop of soybeans and had destroyed flowers and pods. Boom-sprayed at 400 litres per hectare, the insects were killed. Luckily, secondary flowering did occur and a yield of around 2 tonne/ha was taken off. Not as good as 3-4 tonne, but very worthwhile under the circumstances.

Olives at Texas in Queensland were being sucked dry by lacebugs to the extent the leaves were not doing the photosynthesis job to fill out the fruit. Instead of a crop worth between $20-$30 a tree the grower was expecting less than $10 a tree. Using a 1500 litre tank and orchard blower, he treated over 2000 trees at 1.7 litres a tree… 24.8 cents each tree. He followed up with a second spray about 5 weeks later and this saw him through.

One of the biggest Avocado growers on the mid north-east of NSW has been using PyBo for the last 3 years. Trees have been treated with orchard blowers using around 4 litres a tree… 58.4 cents... to control fruit spotting bugs and monoleptas.

Broccoli, basil, lettuce, tomatoes, capsicum, melons and pumpkins are attacked by anything from aphids, thrips, bugs, caterpillars of various sorts and grasshoppers. Treatment by knapsack ($3 a fill) or boom spraying has killed pest populations in minutes. 

Of great interest to baby salad leaf growers, strawberry growers and those who have a constant cropping regime fruit and vegetables can be harvested the morning after the evening spray.  Spay as often as needed to avoid any insect damage that reduces or eliminates acceptance by the retailer.
Growers who use a foliar fertiliser can confidently mix the fertiliser and the Py-Bo together and save application costs.

The concentrate will keep for years, stored in the shed.


Pyrethrum does not discriminate. It will kill beneficial insects as easily as it kills pest insects. However, bees and parasitic wasps are repelled by very low levels of pyrethrum.  If spray time is at around sundown, all bees are safe in their hives and they will not come near a treated crop until the pyrethrum is indiscernible… somewhere about morning teatime next day.If a crop is severely attacked and the grower’s pocket is threatened, there is no hope that ladybirds, wasps, assassin bugs, fungus or bacteria are going to make a significant difference in time to save the situation. But once the crop is saved by pyrethrins, the residue is quickly diminished and, reintroduced beneficials are not under threat.

The same applies in cleaning up an old crop. It can be sprayed just prior to removal and you will not be taking insects outside so they can fly back in again.


Pyrethrum is of very low threat to mammals because it is detoxified so rapidly in warm-blooded systems. Centuries ago the Chinese used it as a treatment for stomach worms. It was dusted all over troops and prisoners in the second world war to kill fleas and lice and reduce typhus.

Not that you should ignore all forms of protection and common sense. If you handle the concentrate or the spray and then touch your lips, nasal membranes or eyes, there will be a numbness and some discomfit for a short time. Pyrethrum makes some people sneeze. If you are driving an open tractor,  a face or nose mask will reduce inhalation of the fine droplets. Wash with soap and water when finished.


The pyrethrum/pbo combination is available in most garden shops and some grower’s co-ops. Many of them are 4g/L pyrethrum at a 1:4 synergist ratio.Pestech Australia sell an 80g/L formulation (20 times stronger and at a 1:6 ratio) especially for serious growers. The registered rate of dilution is 1 ml per litre of water and the treatment costs and examples given in this article are based on Py-Bo.

You can Order on-line pestech.com.au or phone 1800 12345 7. Check with your regular insecticide supplier; we are constantly opening accounts in all areas of Australia.


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