The easiest way to implement such a strategy is probably with non-host plants (see the first answer). Application of methyl salicylate might also get your plants "talking and calling"...but recent research indicates that hyperparasitoids can also cue in to these signals (See Xiao et al 2012, Kaplan 2012). DG James has published several papers where methyl salicylate lures worked to increase the number of natural enemies in crops. This is a promising research area...good topic.

I believe that Hans Visser at Wageningen University pointed out that mixing two different plant species instead of having monocultures should make it more difficult for insect to localize its host plants.

I suggest you go to : http://www.rothamsted.ac.uk/people/jpickett

here you find examples of these types of studies with volatiles and plant metabolites.

A technique that is successfully used for example in Kenya in "push and pull" strategy, which relies on attracting insects to trap crops and deterring them from the crop of interest (for example by intercropping plants that are deterring to the pest, and at the same time attract natural enemies). Here is one example paper: http://rstb.royalsocietypublishing.org/content/363/1491/611.full

The easiest way to implement such a strategy is probably with non-host plants (see the first answer). Application of methyl salicylate might also get your plants "talking and calling"...but recent research indicates that hyperparasitoids can also cue in to these signals (See Xiao et al 2012, Kaplan 2012). DG James has published several papers where methyl salicylate lures worked to increase the number of natural enemies in crops. This is a promising research area...good topic.

A few resources:

James et al. 2012. Employing Chemical Ecology to Understand and Exploit Biodiversity for Pest Management. In Biodiversity and Insect Pests: Key Issues for Sustainable Management, First Edition. Edited by Geoff M. Gurr, Steve D. Wratten, William E. Snyder, Donna M.Y. John Wiley and Sons.

James, D. G. 2003. Synthetic herbivore-induced plant volatiles as field attractants for beneficial insects. Environ. Entomol. 32: 977-982.

James, D. G. 2006. Methyl salicylate is a field attractant for the goldeneyed lacewing, Chrysopa oculata. Biocontrol Sci. Technol. 16: 107-110.

James, D. G., and T. S. Price. 2004. Field-testing of methyl salicylate for recruitment and retention of beneficial insects in grapes and hops. J. Chem. Ecol. 30: 1613-

Khan, Z. R., D. G. James, C. A. O. Midega, and J. A. Pickett. 2008. Chemical ecology

and conservation biological control. Biol. Control 45: 210-224.

Dear All,

I think the neighbouring crops method has had a very old traditional history where the non-host plant volatiles were used successively against some key insect pests. I am afraid this cannot be a Dutch invention, it was used by organic growers in many European countries for a long time.

I believe this is the simplest and cheapest way to use this phenomenon.

Even American Indians mixed two or three different crop species (corn, bean and some Cucurbitaceae) in order to get partly the same output.

Look here for a successful implementation: http://www.push-pull.net/publications.shtml

Hi Ramzi,

there were already very good suggestions given by the others, especially concerning push-and-pull strategies by intercropping. Generally, there are also possibilities to use attractive synthetic compounds in traps combined with spraying or emmission of repellents by dispensers. Some applications are currently in development. I suggest my review article "Gross 2013. Drugs for Bugs: The Potential of Infochemicals Mediating Insect-Plant-Microbe Interactions for Plant Protection and Medicine." You can download it from my research gate site. Further, effective mass trapping is possible for some species by using aggregation pheromones (e. g. bark beetles) or in some cases by kairomones (host plant volatiles).

Hi Ramzi,

Additional to such good feedback from others, an increasing interest has been recently addressed to the use of chemical elicitors which switching on plant defense by manipulating the emission of Volatile Organic Compound (VOCs) to enhance plant attractiveness to natural enemies (predators and parasitoids), increase plant direct defense against herbivore or even alert neighboring plants from any future herbivory. Such benign approach is really very interesting to be implicated in IPM tactics. For more details, I suggest you my paper “The prospect of applying chemical elicitors and plant strengtheners to enhance the biological control of crop pests” Phil Trans Roy Soc B 2014.

Dear all,

Thank you very much for your kind, high-quality contributions, I greatly appreciate them!!

@ Dear Dr. Jürgen Gross, thank you so much for providing a full text version of your interesting publication (book chapter) you mentioned above.

@ Dear Dr. Islam Sobhy, please can you send me a full text version of your article “The prospect of applying chemical elicitors and plant strengtheners to enhance the biological control of crop pests”, I saw only its abstract via internet. Many thanks!!

So, as a summary to all of your contributions, I can write the following sentences:

In this issue discussing manipulation of insect behavior using plant volatiles (allelochemicals that can be attractants or repellents) to enhance overall pest management programs, two sections are to be considered:

1/ Manipulation of insect pests’ behaviors to further limit (decrease) their outbreaks / densities on plants.

2/ Manipulation of the behaviors of insect pests’ natural enemies to further enhance (increase) their host-searching (finding) activity (behavior).

- What can we do for 1/ INSECT PESTS?

Response: plant volatiles can be used a1/ in combination (as kairomones) with sex pheromones in mass trapping, b1/ in attract-and-kill systems, c1/ in push-pull strategies, d1/ they can be employed as synthetic repellents released artificially to disrupt host plant finding by insect pests. Another interesting tactic is that mentioned above by Dr. Islam Sobhy: e1/ manipulating the emission of Volatile Organic Compounds using chemical elicitors to increase plant direct defense against pests and/or to alert neighboring plants from future attacks by insect pests.

- What can we do for 2/ INSECT PESTS’ NATURAL ENEMIES?

Response: Enhancement of plant attractiveness to natural enemies can be achieved a2/ using synthetic herbivore-induced plant volatiles (such as methyl salicylate), b2/ using plant strengtheners (using chemical elicitors), and c2/ by intercropping trap crops (push-pull strategies repelling insect pests from their principal host crop (‘push’) and attracting them into trap crops ‘pull’ that are attractive to pest’s natural enemies )).

However, it should be pointed out that successful applications of these tactics would depend on our degree of understanding of tritrophic interactions’ dynamics (chemical ecology of plant-insect interactions) in a given ecosystem.

Further contributions are appreciated!!

Cheers

Hi Ramzi

Very many thanks indeed for such interesting discussion and also thanks for the overall summary from all contributors… please find the attached paper…happy reading…Islam

Dear Islam,

Thank you so much for providing the full text of your interesting article, great!!.

Best regards,

Ramzi

We have successfully used host flower volatiles to enhance (x50 relative to colour only)a trap for raspberry beetle, a key pest of protected raspberries. The enhanced trap is used for precision monitoring to reduce pesticides and can be used in mass trapping strategies (giving as good protection of fruit damage as conventional insecticides if the pest pressure is not too high). We are also exploring the use of root volatiles to attract or repel root feeding insect larvae (cabbage root fly).

During the last 10 years we manage the pine sawyer Monochamus galloprovincialis populations, the vector of the pine wood nematode Bursaphelenchus xylophilus in Portugal, using traps with chemical lures during flight period. At first we based the lures on pine host volatiles (pinene and ethanol) but the "backgroud noise" of weakened and dying pine present in affected stands limited the captures. After we added to the lures some bark beetles pheromones (ipsenol, ipsdienol and methyl buthenol) that the pine sawyer found to be sensitive, as an adaptative coevolution to detect early stages of pine hosts decline. Since this pheromones are not host volatiles the captures were highly enhace. More recently spanish researchers discovered a Monochamus short range specific pheromone that also improved the traps efficiency. To improve the trap efficiency the lure must overcome the "background noise" of the host plants therefore must contain non-host volatiles that your target-pest is sensitive, considering that you'll never be able to do a better mimic than the real host. Just another thought I would like to share, trapping alone is never enough to control a pest, it must always be complemented by other control measures, at a different ecosystem level (host management, soil and water, etc.).

In our protected raspberry system mass trapping can work as well as insecticides when pest pressure is low-moderate, but not when pest pressure is very high. By trapping inside tunnels, around the field perimeter and also in surrounding (semi-)natural vegetation we discovered that landscape effects and regional climate and scale can have big impacts on mass trapping as a control strategy. A safer strategy is to use traps to detect 'hot spots' within the crop and to monitor movement between host species and crop varieties with different flowering times. We needed several years of data in different regions and countries to figure all this out and design an IPM strategy that is flexible and regionally adaptive.

Birch: sounds very interesting. Do you have any published data on this?

Thank you

I am out of my office but can send you links to technical supports on the application on farms (UK). The fundamental research on flower volatiles is published in journals several years ago.....try searching Google (raspberry flower volatiles, raspberry beetle). i don't have pdfs of these older papers but could look if you are stuck.

Here's another good example of using volatiles to enhance mass trapping:http://www.koppert.com/news-biological-systems/biological-control/detail/mass-trapping-proves-effective-in-many-crops/

Http://www.hdc.org.uk/news-item/new-recommendations-how-avoid-pesticide-residues-protected-raspberry-crops

Dear Ramji, there has indeed been an excellent discussion. However, I must add that all these greatly depend on the target species. For general discussion all this is true. However, when targetting a particular pest, you may have to think suitability of any individual or combination method. We in central India are fighting to manage a dreaded cerambycid heartwood borer, Hoplocerambyx spinicornis using behavioural management, though still in its begining stage.

Dear Dr. Nitin Kulkarni,

Thank you for your contribution. Of course all will depend on the target insect species (and also on the host and non-host plant, so, generally speaking, all will depend on the components of the ecosystem in consideration), this is obvious!!. In fact I already stated this (“may be” indirectly) in my first comment (response) when I wrote:

“ However, it should be pointed out that successful applications of these tactics would depend on our degree of understanding of tritrophic interactions’ dynamics (chemical ecology of plant-insect interactions) in a given ecosystem”.

Good luck in your research studies in India.

Cheers

Check the work of Anne-Marie Cortesero of the University of Rennes 1 in Rennes, France. Interesting and practical.

Birch, can u suggest me some examples of cerambicid management using kairomonal or pheromonal compounds. Presently we are practicing tree trapping method which is based on kairomonal properties, but the isolated compounds does not give better and economical results.

In additionally use of pheromone for management pests, the plant volatile that play a role to host finding and oviposition for the herbivores. If we identify the host volatiles can be used for the attraction of particular insect and can be formulated and use. If we can use both sex pheromone and plant volatiles I think it should give better results.

Here is an example of a high sensitive VOC detection device which is now being commercialized slowly - which could offer early detection of HLB and Asian citrus psyllid, Diaphorina citri in citrus groves. This could be an amazing advancement for early detection and timely preventive disease and insect control all within IPM. Enjoy:

http://westernfarmpress.com/orchard-crops/early-warning-devices-seen-citrus-diseases

Dear Srđan,

Thank you so much for your contribution!! Indeed, this device based on the use of host plant volatiles could be a powerful tool for early detection of pest insects, enhancing overall IPM programs and limiting plant damages and economic losses.

Best regards

Volatil compounds are not all time easy to determine and later on syntetize, My work on a pest Diptera Muscidae Stomoxys calcitrans developed on Pineapple (Annanas) in the tropic of Costa Rica has led us to found that volatil compounds of the plant once is cutted atracct much more flies than other substrates and produces up to 10 times more flies that in regular population of dairies. Volatil compounds are just the key to manage the population, so once we cut plants tissues flies are coming and we do mass trapping or insecticide control for the target sites.

Nuestras tecnologías están basadas en esos principios ecológicos, principalmente en nuestro producto "Biocrack" el cual es una estrategia como se menciona arriba que se realiza en Kenia, es un encapsulado de aromas que se asperjan al cultivo para ejercer la estrategia "Push & Pull" a fin de ejercer una atracción de entomofauna benéfica al cultivo y reprimir la presión del insecto fitófago.

Our technologies are based on these ecological principles, primarily in our product "Biocrack" which is a strategy as mentioned above carried out in Kenya, is an encapsulation of flavors that are sprinkled to the culture to exercise "Push & Pull" strategy to exert a beneficial insect fauna attraction to growing pressure and suppress the hervibore insect.

http://www.bernilabs.com/biocrack.html

For a fairly extensive set of suggestions on this topic, see this paper: http://www.ncbi.nlm.nih.gov/pubmed/15192871

"Induced plant signaling and its implications for environmental sensing"

and this TEDx talk:http: //tedxtalks.ted.com/video/TEDxMU-Jack-Schultz-Eavesdroppi;search%3Atag%3A%22tedxmu%22

The best tool for using VOCs to find infested plants remains the dog's nose. That is the quick and inexpensive way to solve some of these problems. http://www.pressdemocrat.com/article/20060226/news/602260332

Very nice discussion, I guess something similar occurs also for fungal infections

This paper may also be of interest regarding synergy of host and non host volatiles with other visual and olfactory signals:

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0706.2009.16761.x/abstract

Dear Prof. Jack Schultz and Prof. A. Birch,

Thank you very much for your precious contributions; the publications you've mentioned above are very interesting and useful and truly match the subject of our present discussion.

Best regards,

Ramzi

Boosting Prof Jack Schultz point of view, I attended insect chemical ecology (ICE) summer course at SLU (Alnarp) in 2009 and we had an excursion to one of the biggest Swedish forests where they showed us how they using dogs to determine the infested trees with the Park beetles. In all trials, no single mistake as the dog perfectly diagnosed the infested trees.

To manupulate the behaviour of insects and parasitoid in particular host plant can play a promissing and crucial role . Planting for example rows of host plant at the border of the field can enhance the activity of the natural ennemie since it will receive plant volatiles orionatating the parasitoid to nutrional ressources then the activity and the  the parasitism rate will increase . It is a kind of managed landscape . Another approach can be used for pest control is to plant crops releasing plant volatiles that are repulsive to the pest . the enviroment will be chemically saturated by these repulsive VOCs and the croo protected.

In continuation with the discussion, here I would be interested to share my experience with Shorea robusta trunk borer, Hoplocerambyx spinicornis. I have successfully identified a few chemicals responsible for pheromonal and kairomonal properties. However, I need those chemicals for final bioassay. These are not available in market even with sigma. While they are shown as available with some Chinese firms, but they do not seem to be reliable. I would like to request the experts here, how do other researchers carry out further researches in such cases. That will also help Ramji for carrying out the work.  

Dear Takoua and Nitin,

Thank you so much for your interesting contributions providing useful research lines linked to our discussion on ecological basis / involvements of using plant volatiles for manipulating insect behavior. In the framework of our discussion, I’d like to invite you to read an interesting article (discussing other aspects focusing on plant–pathogen and plant–insect interactions) through this link:

http://www.uu.nl/sites/default/files/functionalecology-ponzio-2013.pdf

Best regards,

Ramzi

Great publication that would help me a lot. Thank you

Dear Ramji and Takoua

Undoubtedly, attached publication is very well written and useful. I think Dr. Takoua and others can also answer second part of my comment ie.,  

I have successfully identified a few chemicals responsible for pheromonal and kairomonal properties. However, I need those chemicals for final bioassay. These are not available in market even with sigma. While they are shown as available with some Chinese firms, but they do not seem to be reliable. I would like to request the experts here, how do other researchers carry out further researches in such cases. Can anybody through light ?

Dear Nitin,

Please can you specify which kind of chemicals and from which plants you've been identifying? The bioassay would also depend on the targeted insect pest you will work on. And I do not understand why you told that these chemicals available in China " do not seem to be reliable" Did you really tested them?. There are several research articles exploring what you need exactly (Materials and Methods), all depend on the key points I've mentioned above.

Best regards,

Ramzi

Dear All,

Use of host plant and synthetic volatiles has a relevance in pest forecasting. They can attract some pest species like European corn borer or some important noctuid species. The trouble is that these attractants have quite a wide action spectrum thus they attract many pollinators and non target indifferent species. In Hungary, phenyl acetaldehyde, beta ionone, methyl salicylate, beta-caryophyllene, isoamyl alcohol etc. are widely used in forecasting and in research experiments. Many combinations have had strong side-effects killing many thousands of pollinators (honey bees, bumble bees and other bees) and other indifferent species which made 40-70% of the whole catches. It is a pity that some researchers think that they can freely use without the necessary responsibility the natural diversity of faunas for lucrative aims.  They did it in the name of integrated pest management. How long can be continued this kind of natural protection?

Here you can find a review on herbivore-induced plant volatiles:

https://www.researchgate.net/publication/251638027_Attracting_carnivorous_arthropods_with_plant_volatiles_The_future_of_biocontrol_or_playing_with_fire

Article Attracting carnivorous arthropods with plant volatiles: The ...

Dear Prof. András Bozsik,

Thank you very much for your precious contribution in this discussion and for the interesting article you've provided !! Yes I agree with your statements and any use of such volatiles would strictly depend on the nature of ecological / trophic interactions and conditions in a given ecosystem.

All the best,

Ramzi

Hi,

As said Jan Adrianus Veenstra , in Hans Visser's group (Wageningen), mixed stands of vegetation ( intercropping) were investigated in potato/colorado potato beetle (using wild solanacea or cabbages), nicely showing how plant odour camouflages may opperate. Publications on my gate or on Hans Visser's site.

Denis

Dear Dr. Denis Thiery,

Thank you very much for your presious contribution to this discussion.

Best,

Ramzi

Dear all,

In the framework of this discussion I would like to invite you to read this interesting article (by T. Turlings and M. Erb) recently published in Annual Review of Entomology (Vol. 63: 433-452):

Tritrophic Interactions Mediated by Herbivore-Induced Plant Volatiles: Mechanisms, Ecological Relevance, and Application Potential

Article Tritrophic Interactions Mediated by Herbivore-Induced Plant ...

Best,

Ramzi

Hi Dr. Ramzy,

I am highly recommending such recent published review by Ted and Matthias in Annu Rev Emtomol. Additionally, please find the attached other recent reviews that are cover such point.

hopefully that would help.

Best regards,

Islam

Gish et al., 2015

Stenberg et al.,

Heil 2014

Hi dear Dr. Islam,

Many thanks for your great contribution by providing all of these interesting articles. I'm really happy to hear from you.

All the best,

Ramzi

Hi Dr. Ramzi,

Thanks a lot for your words. Indeed, the discussions that you always suggest are very interesting. I wish you the best for your research.

Best regards,

Islam