Hello Srdan,

Another alternative added to the above list that proposed by Dr Sidhu is the use of Plant Elicitors or activators which increase the plant immune system and induce its resistance against pathogen by eliciting the salicylic acid SA pathway... For more details, please check the attached paper.

Regards,

@ Srđan G. Aćimović,

These are some point which may be helpful.

1) Look for resistant varieties.

2) Find alternate biological control.

3) Make sure that seed should be disease free.

4) Give seed treatments other than fungicides as preventive measures.

5) Crop rotation may also be helpful.

6) Elimination of alternate host of the fungus if possible.

7) Proper Irrigation and fertilizer application can control the disease.

8) The diseased plant should be removed and buried deep in soil.

Regards

Hello Srdan,

Another alternative added to the above list that proposed by Dr Sidhu is the use of Plant Elicitors or activators which increase the plant immune system and induce its resistance against pathogen by eliciting the salicylic acid SA pathway... For more details, please check the attached paper.

Regards,

Breeding for disease resistance utilizing the tools of genetic engineering can be an option. However, both genetic resistance and selective fungicides are prone to adaptation by the pathogen. As such, major multi-national companies are focusing their future on an integration of genetic traits and agrochemicals Biocontrol products currently contribute less than 1% of the fungicide market and expected to contribute more in the future, with the natural compounds known as biopesticides. Use of antimicrobial peptides (AMP) for improving resistance to pathogens using transgenic plants as bio-factories for fungicides or bactericides is now-a days an interesting new area of research. Equally important for sustainable disease control is the intelligent integration of these technologies with sound cultural and sanitation measures.

Apart from above mentioned methods ,one can also try to grow trap crops to divert the attention of pathogen from main crop to more susceptible host grown to trap the pathogen and then discard it. It will help in reducing the disease inoculum for coming years. Biological control agents and Integrated pest management strategies may prove helpful as well.

All the above approaches you all mentioned might be the the key components in successful pathogen/pest control - depending on the plant species and environmental conditions, and also the pathogen/pest species. However, with all new approaches and technologies there are (new) hurdles that occur - sometimes inadvertently - and which further bring economic losses. For example, glyphosate-ready corn turns to be a huge weed problem in the next season with sugar beet and soybeans as a crop, within a normal crop rotation schedule. Second, mulching with straw in strawberry fields for prevention of fruit contact with soil and Botrytis rot allows increased incidence of Phytophthora crown rot. Further, BT-ready corn already has a new issue - the Western corn rootworm, Diabrotica virgifera virgifera is reported to develop resistance to BT-ready corn. So in the long run, the integration of genetic traits and agrochemicals might be the best approach but we still need to be prepared for any side effects that usually are not perceived as possible while the new technology is invented, tested and finally released for commercial use. So it seems to me that new models of statistical estimating of the immediate and long-lasting advantages of new technologies need to be developed so that we can predict or anticipate these problems and be ready for them - before whichever the technology is proposed to be patented - is released for commercial use.

We definitely need to address this possibility now. I believe that our best bet would be Biological Control. It seems that before the advent of chemicals this was prevalent. We need to revert back to it.

Some of the biocontrol agents we have today are also growth promoters. We need to tap into such areas.

With this comes the use of cultural practices as well.

Dear All,

I think there is no magic bullet. Pesticide (over)use is a comfortable situation and so many growers forgot thinking how to avoid pest or pathogen attacks by traditional agricultural methods like crop-rotation, timing of sowing, crop care, right crop nutrition, right varieties, selection of the proper soil and situation etc. All these kinds of technology were substituted by pesticides. Thus, one should study and practise crop production as it is proper from point of view of the crop and not that of an investor. But this needs knowledge, experience and continuous observation and care of the fields and plantations.

Dear András and Jaleed,

I agree that the time to address this issue and act is even yesterday. We would all wish that biological control practices are currently really up to the task - so to speak. In many cases they are not - unfortunately. Further, some other aspects of biological control - such as release of saprophytic antagonistic bacteria or attenuated mutants of pathogenic bacteria which control the pathogen, are sometimes burdened with legislative bans due to the potential side-effects and danger to the animal and human health, and even gene transfer issues via plasmids. Further, it was shown that war against pathogenic bacteria in phylloplane is hard and requires preventive and frequent treatments. I can go on with other examples.

Yes, there is no magic bullet. I have been hearing around that some important fungicide classes will be restricted heavily, if not completely banned in future - due to interference issues with animal and human hormonal systems. What does chemical industry have as a new ace for growers in the future? András I hope you are right. I've seen a lot of growers with relaxed attitude - I'll spray and forget about it. That might no longer be an option - and the growers globally will need to learn more and take care of their crops in much more advanced mode than before. The reason I think it will be more difficult is the fact that we grow our crops on high acreages - for high yields - and that increases the magnitude of all problems once pathogen/pest occur. It will be hard to go back to the "old methods" once some fungicides are out of the choice for use - since it is more time consuming, potentially more expensive and highly demanding from the learning-curve point of view.

There is no short cut to fungal problems, apart from rotating fungicide with different modes of actions, the only sustainable way is to adopt an IPM approach. These two Biorationals have worked so well in cut Flower and vegetable as well as wheat farms in Kenya. They work as growth promoters as well as fungal pathogens control. They are stable in the soil and once established their effect lasts longer.

1.Trichoderma asperellum an antagonistic fungus that is used globally for control of soil borne fungal diseases including Fusarium spp., Rhizoctonia spp., Sclerotinia spp., and Pythium spp. Its mode of action include mycoparasitism, antibiosis and competition. In addition, this strain is known to have the ability to increase plant growth vigour

2. Arbuscular Mycorrhizal Fungi (AMF) - Mycorrhizal fungi are beneficial organisms that occur in association with plant roots in nature and enhance plant growth and vigour. It forms a network of fungal hyphae around the feeder roots of the plants. Mycelial threads penetrate inward into the root cortex and across the soil around the roots thereby increasing the surface area for absorption and translocation of essential plant nutrients including Phosphorus, Nitrogen, Sulphur, Calcium, Zinc and copper

My company due to demand has worked to combine them into a single product together with Paecilomyces lilacinus a naturally occurring Nematophagous fungus to control arrange of soil born pathogens

Dear Sobhy and Otieno,

It is great to hear we have functioning and applicable models of real-time situations - that work efficiently. That is what we need. A lot of data exists on vegetables and flowers. However, the situation is much more problematic in cultivated tree species. Somehow, the SAR and ISR inducers or plant resistance elicitors you mention above are just not efficient enough option - for now. Currently plant resistance inducers are weak overall to provide efficient control of fire blight Erwinia amylovora on apple, for example, and hence are rarely registered around the world for this disease. The effect of elicitors needs to be boosted up to be more effective.

Dear Srdan,

I am totally agree with you regarding the elicitor applications on tree species. However, Holopainen group in Finland showed some promising work on the use of chemical elicitors on Conifer trees. For more details, please see the attached paper.

Regards.

Thank you Islam. This paper is very very interesting and encouraging. Thank you for sharing this paper with us. Best,

S

Dear all,

in integrated pest management there are always alternatives. This is part of the concept. We shall not forget that the major advantage of "cash crops" and the use of pesticides in conventional farming is cost efficient food production. Crop rotation, mixed varieties and species and soil tillage are among the oldest and most efficient tools for pest management (COST Action 817; Newton, A.C., Guy, D.C., Bengough, A.G., Gordon, D.C., McKenzie, B.M., Sun, B., Valentine, T., Hallett, P.D. 2012 Soil

tillage effects on the efficacy of cultivar and their mixtures in winter barley. Field Crops Research 128, 91-100). Generally most alternatives mean a penalty on the input (higher) or on the output (lower) (keyword "cost of resistance). The ratio varies greatly between agricultural and socio economic environments. This needs to be taken into account when optioning for one and restricting other control and management tools. While there is a high awareness of this context among people involved in agriculture and horticulture, it seems not to have reached the consciousness of consumers and decision makers.

Although the mentioned alternatives sound oldfashioned and simple they remain poorly understood in there complexity. Research has long been neglected and needs urgently to be encouraged. Some pesticide companies are taking first steps into this direction, probably for good reason.

Dear Michael,

I am glad you mentioned the cash crops or how we refer it here as high value crops and how do pesticides couple with the concept of feeding the world. It seems to me that during the era of chemical plant protection in 60s and 70s, the research on other methods of disease and insect control got delayed until the "Silent spring" by R. Carson came out and rose our and the society's general awareness. Then IPM took off and researchers throughout the world pressed-on to give more environmentally safer solutions and "soft" chemicals for treating crops. And then the problem of complexity in understanding IPM and agro-ecosystem came in - and researchers, growers and economists realized that IPM is going to require much more knowledge to implement and much more input as you said - read money. I have encountered many times this disconnect you mentioned between the growers, economists and consumers - the disconnect of differential perception of how and where our food comes from, under which conditions it is grown, and how much it should/does cost. I am also on the side that research needs to address this disconnect more and bridge this gap so that we can generate solutions we can lean on more in production.

Best,

S

Remember my dear friend, that when a fungicide or pesticide or herbicide etc is banned, it is always replaced with a better and efficient one because ultimately you have to do an efficient disease management and not suffer a huge loss in crop yield.

Dear Jai,

looking back I can agree with your point of view. Still in Europe we might reach the limits of this process if we ban a major pesticide class like the DMI s for a difficult to evaluate trait like endocrinic effects. It would be better if we had the alternatives first. Some emphasis is put on IPM projects to compansate effects through more efficient combination of control strategies, but most tools (models) are more descriptive and based on current and old data. They are not necessarily able to master future challenges. The major advantage of pesticides is the rather short time of development compared to crop resistance or cropping system, but you need a choice. Relying on only few modes of actions is risky. This is more and more the case.

In the end I see a major responsibility, because if there is a great loss in crop yield, it is probably not the Europeans that will suffer the most.

Best M

Thank you Jai. I hope you are right. However, I would remind you on how much it has become harder to register new fungicides (besides insecticides and herbicides) in the last 15 years. Not only the bad publicity for example with Imprelis or neonicotinoids in general, made this process very slow and hard, but also the scientific findings which are explaining the causes of unexplained problems such as colony collapse disorder in bees, came into the focus and further made the pesticides registration incredibly hard. In crop protection situation is better, I agree. However, that is not the case in all branches of agriculture. It is obvious that many changes are about to come.

Sooner or later, IPM would be deployed in all fields of agricultural sectors worldwide. Alternative to fungicide through IPM program should include in this case quarantine, resistant or tolerant varieties as well as biocontrol tactics including PGPR

Thank you Dr. Mandour. My research group is investigating how could we integrate trunk injection of plant protective compounds in integrated pest management in tree-based agriculture. Even though laborious, we think this concept of compound delivery to tree canopy can eliminate pesticide drift and reduce side effects of pesticides to the environment. If automated i.e. if the trunk injection technology from landscape tree care is improved to increase the efficiency of injection process we could integrate it in fruit tree protection. However, a lot needs to be done. I would like to hear your opinion on this matter.

Precise agriculture - no one from that area of research feels invited to comment further? 

Chemical fungicides are harmful to environment and human being, So that we suggest farmers to use phytofungicides for management fungal diseases.

See the attachments for the answer to your question.