Frequently Asked Questions
This page contains a selection of frequently asked questions, click on the section that is most relevant to your question to jump straight to that section of the page. If you can’t find the answer to your question here, contact us using the form on the Contact Us section of the website.
Monitoring
Traps and lures from different manufacturers often catch different numbers of insects. Is the pheromone lure which catches the most insects always the best choice?
Not necessarily. The most important consideration is consistency of performance. Pheromone traps are sampling devices which provide information on the insect population. It is very important that the trap catches a consistent proportion of that population. Pheromone lures are controlled release devices that release the pheromone as constantly as possible. Lures which attract a large number of insects at first but catch fewer as the pheromone release rate declines will not provide an accurate picture of the insect population.
Does a higher loaded lure always catch more insects?
Pheromone lures are usually designed to mimic the natural pheromone release of a female moth, for example. If the release rate is too low, then the lure will be less effective. However, the dosage can only be increased within certain limits. If the loading is too high, then the response of the male (in this example) may very well decline.
How important is the percentage purity of the pheromone?
While the percentage purity is of course important, it is the nature of the impurities which need to be understood. Certain impurities, for example different isomers of the main active isomer, can actually be repellent to the target insect.
How many traps per hectare do I need for monitoring?
This depends on a number of factors including the objectives of the monitoring programme, the identity, mobility and typical distribution of the insect pest and the size and homogeneity of the area being monitored.
Is there always an exact relationship between pheromone trap catches and infestation in the field?
For some insects like codling moth or pink bollworm there is usually a good correlation between the numbers of male moths caught in pheromone traps and subsequent numbers of eggs and larvae in the crop. For other insects, such as American bollworm the relationship is less clear.
Why doesn’t your Technical Data Sheet indicate any thresholds for the target insect?
Pheromone trap thresholds vary from country to country and region to region. They are established by the local research and plant protection services.
Sticky Fly Traps
Can I control whiteflies in a greenhouse using yellow sticky traps?
Yellow sticky traps can be used for both pest monitoring and population suppression. 10 cm traps are usually preferred for monitoring purposes while 20 or 40 cm traps can be used for mass capture and population suppression. When used in this way, they should be considered as preventative devices. They will not bring an existing high population under control and should be used with other control measures such as the release of biological control agents, such as Encarsia or certain IPM compatible insecticides such as Azatin or Neemix which contain Azadirachtin.
How important is trap colour?
There are no chemical attractants on these traps. The insects respond purely to either the yellow or blue colour of the traps. The blue is specific to the Western Flower thrips while the yellow works for a wide range of insects. The level of attraction depends on the precise characteristics of the colour. AgriSense traps have been optimised to maximise the attraction of pests.
Mass Trapping
How many traps per hectare do I need, to control an insect by mass trapping?
It is important to understand that not all insects can be controlled by mass trapping. It is also better to think in terms of population suppression rather than control. The most promising candidates are insects that use aggregation pheromones such as Spruce bark beetle (Ips typographus). For this pest, trap densities of 20 – 30 traps per hectare have been used.
When Lepidopteran sex pheromones are used it is important to remember that only male moths are caught in the traps. The females, which lay the eggs, are not caught. Because a single male moth can inseminate a number of females, it has been estimated that it is necessary to catch 95% of the male moths before there is any significant impact on the ability of the population to reproduce. Any moth pest which is quite mobile such as Helicoverpa armigera will not be successfully controlled by mass trapping, simply because females that have mated outside the trapping area lay eggs in the area where the males may have been successfully removed.
Mass trapping has been shown to work successfully for moth pests which are relatively immobile such as certain rice stem borers (Pyralidae), potato tuber moth (Phthorimaea operculella), diamond back moth (Plutella xylostella) and brinjal fruit and shoot borer (Leucinodes orbanalis). For pests such as these, trap densities of 10-20 traps per hectare have been shown to be effective at reducing damage levels.
Attract and Kill
What is the difference between Attract and Kill and Mass Trapping?
The term Attract and Kill (or Lure and Kill) is normally used for pheromone (or other attractant) based control methods that use an insecticide to kill the target pest. Mass Trapping, as the name implies, depends on the use of a mechanical device (insect trap) to remove the insect from the population. From a theoretical point of view, the approaches are very similar. Both methods rely on attracting the pest to a pheromone (or other attractant) source and removing the insect from the breeding population.
Mating Disruption
Why are more moth pests which have sex pheromones not controlled using mating disruption?
To develop an effective mating disruption product a number of conditions all need to be fulfilled:
i) The target pest needs to be relatively immobile in order that females that have mated outside the treated area do not enter and lay eggs in the treated field or orchard. American bollworm (Helicoverpa armigera) is a good example of a very mobile pest that is very difficult to control with mating disruption unless thousands of hectares are treated simultaneously.
ii) The pest should ideally be restricted to a single crop; otherwise all target crops within an area would require treatment.
iii) The pheromone can be synthesised at an economically acceptable cost. Spiny and spotted bollworm (Earias insulana and Earias vitella) can be readily controlled with mating disruption but the method is not economically viable due to the very high cost of the pheromone.
iv) The pheromone must be stable and able to be formulated in a controlled release system that can be readily applied to the crop.