Crop Protection - Science topic

Sources of resistance to early blight, Alternaria solani, and transfer to tomato, Lycopersicon esculentum

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Sources of resistance to early blight, Alternaria solani, and transfer to tomato, Lycopersicon esculentumArticle

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Tomato entries reported as early blight resistant were collected and evaluated under severe early blight infection in the warm rainy summer months of 1982-1985 in Mayagüez, Puerto Rico to identify sources with useful resistance in Puerto Rico. Of the common tomato lines, 84B 510-4 was the closest in resistance to the best wild tomato species, which are less susceptible to early blight than common tomatoes. Useful field resistance was found in the minority of cases, but one or more entries of L. esculentum f. cerasiforme, L. pimpinellifolium, L. esculentum X L. pimpinellifolium, and L. hirsutum var. typicum showed useful early blight resistance. Lowest disease ratings were found in varieties of L. hirsutum, which also showed the lowest yield. Better fruiting was found in L. pimpinellifolium although resistance levels were slightly less. Crosses of L. pimpinellifolium and L. hirsutum with useful early blight resistance to susceptible L. esculentum were followed in F1, F2, and F3 generations. Resistance appeared partially dominant from F1 disease ratings, and segregation in F2 suggested that many modifying genes both dominant and recessive were probably involved in conditioning early blight resistance. Generally, common tomatoes appear much more susceptible to early blight than wild species. To enlarge the pool of early blight resistence genes, F2 selection and progressive back crosses are suggested. Susceptible tomatoes were defoliated by early blight within one month after first flower during the warm rainy months; whereas, entries with useful resistance defoliated from 6 weeks to 2 months a​

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Tetracycline , streptomycin and Copper fungicide help to reduce spread of this bacteria

Best regard

Also check please the following very good RG link:

These plants also include Cinerarieliste Feverfew (Dalmatian chamomile), the extract of which served as the basis for a bio-insecticide. Such a seemingly harmless flower grows on the Balkan Peninsula off the coast of the Adriatic Sea, and is also cultivated in the North Caucasus, Central Asia and some European countries.

As a result of high-tech processing, Pyrethrum (pyrethrum) is obtained from the inflorescences of mountain chamomile - a contact poison that enters the insect's body through the chitinous cover or the respiratory system, and then spreads through the body through the cavity fluids, causing paralysis of the nervous system.

Dear patrick .

please see attach paper

Best Regard

Drought triggers a wide variety of plant responses, ranging from cellular metabolism to changes in growth rates and crop. water loss control and a protection mechanism to tissue dehydration in plants is also useful.

COVID 19 impact on Agriculture, especially Crop Protection

This might be informative also, Dr. Eduardo V. Trumper

Over watering is the main issue in papaya trees. We have practical experience at our farm on variety Red lady. Papaya should be planted on raised bed. Irrigation should be restricted to furrows only. The water should not touch the plant in any condition. This crop is very sensitive to water logging.

Dear colleagues,

Many thanks for your kind support.

I will go through the papers and links you have provided.

Best regards,

Giorgio

Crop Protection and Its Effectiveness against Wildlife: A Case Study of Two Villages of Shivapuri National Park, Nepal.

Hope this may be helpful

There is another link on this topic: https://www.researchgate.net/post/What_exactly_is_the_sublethal_dose_of_a_drug_and_how_i_measure_it

Found this information:

1. Sublethal effects are defined as biological, physiological, demographic or behavioral effects on individuals or populations that survive exposure to a toxicant at lethal or sublethal dose/concentration. A sublethal dose/concentration is defined as inducing no apparent mortality in the experimental population. Ref.: )

2. EC50 (median effective concentration): The concentration of chemical in water to which test organisms are exposed that is estimated to be effective in producing some sublethal response in 50% of the test organisms. The EC50 is usually expressed as a time-dependent value (e.g., 24 h or 96 h EC50). The sublethal response elicited from the test organisms as a result of exposure to the chemical must be clearly defined (e.g., test organisms may be immobilized, lose equilibrium, or undergo physiological or behavioral changes). (Ref. Book: Handbook of Toxicology, page 948. Editors, Derelanko & Hollinger, 3rd Edn., CRC Press).

3. EC50 (effective concentration–50%): A statistically or graphically determined concentration of a chemical that reduces a sublethal response parameter of interest by 50%. (Ref. Book: Haye's Principles & Methods of Toxicology, 6th Edition, page 2084).

4. Most toxic effects in polluted ecosystems are sublethal and so sublethal tests should be used in order to assess the likely effects of pollutants. This can be done by determining the median effective concentration (EC50). This is the concentration of added toxicant that in a given time under given conditions brings about a specified sublethal effect in 50% of the test population. Such an effect might be a 20% reduction in growth rate relative to a control with no added toxicant. It could also be a 20% change in any physiological process, such as a 20% reduction in photosynthetic or respiratory rate relative to a control, or a 20% change in a developmental process such as the formation of reproductive bodies in an alga. (Ref. Book: Fundamental Toxicology, 2006, Editors: Duffus & Worth, page 268, RSC publishing).

You can see:

https://pdfs.semanticscholar.org/8a9f/268129536818b5daf4a068a8aa4e8f357d73.pdf

It is not only due punctures produced by the probing proboscis of true bugs but some fungal or bacterial infection occuring after suck

satish

Great work. Good Luck!!

Trust Donga

Hi Olli ;-)

I would like to add that wolves - and i am sure this this is the case for other mammals too - are capable to adjust to noices. This is the reason why livestock protection measures in the form of acoustic devices were provent to be effective only temporary (because they do not harm the animal). Another example are wolves on military training grounds. The military sounds seem to leave them cold. Probably because they are part of their environment and they do not link those sounds to danger or pain.

Genetic erosion is the disappearance of genes/alleles from gene pool and reduction in the genetic resources of the earth. Twentieth century has witnessed a loss of 75 per cent of genetic diversity of crop plants. Genetic erosion occurs due to crop number and crop varieties. Originally a large number of plants were utilized for different uses but gradually the number of exploitable plants has decreased. For example, out of 3,000 food plant species only 150 were commercialized. Agriculture is dominated by only 12 species out of which four yields more than 50 per cent of the total (rice, wheat, maize & potato). In recent times there is a tendency to incorporate the maximum good characters in a single variety. As soon as better variety is developed the same is distributed far and wide and brought in use consequently the local indigenous varieties are discarded and their specific alleles are lost forever.

The genetic erosion is a matter of serious concern as it will hamper the crop improvement programme. The traditional varieties of crops and their wild relatives possess several useful genes, which may be exploited for the improvement of crop varieties through crop breeding. Thus the maintenance of a diversity of crops with different characteristics gives the community a buffer stock of food, if droughts or floods or pest attack occurs.

I do not think that it is an abnormality. These are called husk leaves and the character is under genetic control. The expression of this character would depend on the fertility of the soil and nutrition. In highly fertile soil and good growing conditions the expression would be more. This character is heritable.

Dear Marc,

Check out also the work of Peter Rosset (especially the work he has been doing in Cuba).

Dear Seidal,

As you know from your searches, a limited amount of information on the potential impacts of climate change on plant harmful organisms is available. It is known that extreme changes of climate affect plants in natural and agroecological conditions throughout the world. These changes directly impact plants and their interactions with harmful organisms. In addition, there is clear evidence that climate change is altering the distribution of plant harmful organisms, but the full effects are difficult to predict and need to be assessed on a case by case basis. From my point of view, extreme climate changes will affect pests, yield and quality of meadow fescue. The prediction is that extraordinary weather conditions may alter rates of pest development, affect host resistance and lead to changes in the physiology of host - pest interactions of meadow fescue. However, can’t say that how much this conversion will realize. It needs to be studied.

Good luck

Thank you for your applications! The application process is now complete.

Hi dear Rouhallah,

Thanks a lot aziz.

Hope to see you soon

Friendly Yours

Behzad

My guess is that it is a cutworm of some sort: the larval stage of a moth in the Noctuidae (it might be some other caterpillar, but cutworm is a very common situation). The mosquito netting suggested by Kulvir is an excellent idea. Insecticides could be used, but they might affect your experimental results. The netting will reduce sunlight. Usually it is not enough to cause problems, but that depends a great deal on your research question. You can get fancier, make a cage with netting on all sides and a clear plastic roof. Be careful about the ground. cutworms hide in cracks in the soil, and are experts at finding or making a hole in your netting. They also hide in the soil in pots. It might help to build a table. The legs of the table can be put into small cans of oil or talc powder or soap. Alternatively put something like tanglefoot on the legs. Then the cage can go on the table, and the new plants in the cage. If you use old plants, you might be bringing the pest with you.

Dear Hanna M. Madanat Thanks for help.

20

Dear Al-Ani,

I really appreciated your kindness for sharing these many interesting books and other documents.

Kind regards.

Si Bennasser

Dear All,

Also some endosymbiotic bacteria can cause colour change in aphids

Can you please add some information about soils also.. to help identify the problem precisely...

20

Hi James,

I did not work with hapmap data for long, but I remember that some genotype files were available.

I think (but not sure) that column named 0 and 1 refer to the same individual. you could check that by counting columns and the number of individuals.

Hope it help.

Dear Allen

for detecting herbicides using fast blue BB dye were reported to be successful. 

for more information take a look at attached pdf

It is more likely that the pesticide will get bound in the plastic. Most likely adsorbed, but possibly chemically bound or diffused into the plastic. This may be good or bad.

Good: the dose that you apply is likely the dose experienced by the insect.

Bad: the dose that you apply in the field can be adsorbed, absorbed, or bound to the leaf surface. What you would like is a petri dish that mimics the physical/chemical properties of a real plant. Then you have a more realistic dose transfer model as the pesticide gets from the plant to the target insect.

Ugly: pesticides are seldom applied as a pesticide+diluent. Typically there are a range of adjuvants that are included in the formulation. These adjuvants will affect the physical and chemical interactions between the pesticide and the petri dish as well as the transfer of pesticide from the petri dish to the insect.

To make life simple, use glass because you don't know what you are getting with plastic.

You might argue that a plastic dish assay is more relevant because your application is to baseboards and floors for pest management in homes. This seems reasonable, so long as you are using the same plastics. The effect on HDPE will likely be different than the effect on polystyrene (or any other class of plastic).

If you can, match the application method to the expected application method in the field. The distribution of deposits on a surface (any surface) matters. What looks like a uniform coating to a person might have large gaps to an ant.

19

..

We have 165 grassroot practices to control White fly, See below links

ICARDA scientists are working on this area.

For the U.S., the Crop Data Management Systems free database is the standard:

Also Agrian:

Higher transcription rate of some regions relating to resistance maybe?

 Yes it is possible, we need to grow trap crops with main crops. There are identified different trap crops for main crops such as okra, maize for different situations. Few of the trap crops reported are:

Nasturtiums are very attractive to aphids (blackfly, greenfly, whitefly) which will often completely cover the stems. Expect to see ants 'farming' the aphids for the honeydew they release.

Nettles also attract aphids and because they do this early on in the season they are often followed by beneficial insects such as ladybugs.

Chervil is said to be very attractive to slugs.

French Marigold is variously reported to attract slugs, thrips and nematodes.

Radish is said to attract flea beetle and root fly away from cabbages although various other brassicas can be used as trap crops too so it is best to experiment with Chinese cabbage and collards as well.

Please see following publication:

Rice Co has a WG formulation that does not presents those problems 

 The Integrated Crop Protection (ICP) extension project aims to promote best management practices for plant health in the Australian vegetable industry, including responsible chemical use. Protecting crops is vital for vegetable producers to improve productivity, profitability and sustainability. However practices, capabilities and attitudes differ throughout the country. The project is continuing to work with growers, advisors and other industry service providers to tailor solutions that suit their circumstances.

1 You can incubate the wheat seeds a few hours with a solution of Rhizoctonia Cerealis and then sow.

2 You can sow seeds in plots and in 3-4 days for example (when the plant has grown) you can irrigate with Rhizoctonia Cerealis solution (previously grown in liquid medium). Be careful if you make slits because the roots of wheat are thin and I imagine you'll want to reproduce natural conditions pathogen colonization.

Crop Damage by Excessive Rain, Ponding, and Floods

Excessive rainfall results in saturated soils, ponding of water on the soil surface, or outright flooding of major agronomic crops somewhere in the Asia/India sub continents every year. Individual growers and their consultants, however, may experience such crop damage only a few times in their careers and so often have little experience in assessing crop recovery or identifying economically viable crop management decisions in the aftermath of the damage.

Flood-related crop management information written by crop experts from throughout the U.S. Corn Belt. The articles are organized by subject area. You can either scroll down the page to locate an area of interest or click on the list below.

1. Assessing crop damage.

2. Crop insurance.

3. Disease management.

4. Forage management.

5. Harvest issues.

6. Insect management.

7. Late planting & replanting concerns.

8. Miscellaneous.

9. Nitrogen loss.

10. Weed management

Hi Imran,

We used the vector pK7GWIWG2D, (Gateway technolgy, from Invitrogen) that was really practice and fast to contruct. It is a little expensive but useful. It has 35S promoter and Kan resistance to plants selection. It is a vector to generate silencing of some gene/s. Please find attached our paper where we use it.

All the best!

Thanks Clifford B Keil 

I had reviewed the Patricia´s work

This Cecidomyiids causes galls and galleries on the stems during the cultivate cycle, we didn´t find them in the seeds. The crops were located between 2590 and 2740 m s nm, less than this altitude we didn´t find de pest 

Regards 

Catalina

 An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase).. Emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the liquid matrix (called the “dispersion medium”) are usually assumed to be statistically distributed. The said ingredient makes more emulsifiable the formulation  I guess

I must say that I have never worked with Sorghum, so I can only give an answer based on the theory. As tannins are aromactial compounds I would expect an EPSPS overexpressing plant to accumulate more tannins compared to wild type plants. This may in turn give the plants enhanced resistance to herbivores.

Thank you for your kind and quick suggestions

Pyroxasulfone, saflufenacil, mesotrione and 2,4-D are some good options available for conventional weed control on corn.

You may want to consult a Weed Control Guidelines of your state.

If you're interested on testing products based on natural compounds, I've attached a publication with some examples you may want to look at.

Good luck on your research!

Hi Elfanah,

Best solution is to use reflective mirror bird scarers. This is a just a moving mirrors sparkle in the light, using the natural energy of breezes and the sun. Highly recommend :) 

In old days we had used cassette tapes over the field to give reflections (specially parrots, sparrows)  But now common practice is to use CD's 

dear András,

in Italy, at present the Asian ladybird is not considered a major problem in grapes (vine growers are much more concerned about Flavescence dorée), whereas it causes some trouble in houses during winter. I made some random observation on grapes without detecting it.

This paper is about enumerative sampling plans for H. axyridis in grapes:

In a previous work on the effect of neem tree extract on Spodoptera , I had some photos similar to yours and alsosome aberrations in the pupal stage. Neem extract is a growth regulator and feeding deterrent. May black pepper oil has the same mode of action.

If you are interesting, investigate the fecundity and fertility of the insect after treatment and also the reproductive system of both males and females because they are affected by these types of growth regulators.

All plant breeding results into resistance against targeted pests, sooner or later. Fact is that with Bt crops the reaction will be easier and quicker and up to now it is not really a big concern. Hope you have the publications of  Bruce Tabashnik, if not, just come back, cheers, Klaus

Dear Doctor Rao

In terms of the Phosphorus questions the synergism of legumes through Rhizobia stimulate the mycorrhizal system the stimulated to mycorrhizal fungi  promote Rhizosphere communities of fungi and bacteria that have Phosphorus mobilizing capacity the plant, bacteria and fungi work together synergistically when the system is optimized for them.

These synergistic symbiotic approach required distinctive nutritional support  aimed at supporting the symbionts for the synergism to be most effective. They are especially dependent of micronutrients such as Mo Co and Zn to be most effective and need to evaluated much more thorough.

Symbiotic synergistic is a way of getting more for less and changing negative environmental and energy footprints into positive ones. These solution are systematic in their nature and need interdisciplinary collaborative focus and coordination.

Thanks to all of you for your quick responses!

@Hr. Otto: I'm not limited to Brazil or the USA, I used those countries for the example. The different water rates in Germany or France are interesting, too. Anyway I'm searching more for the rates used in the agricultural practice -> in the 'farmers fields'. So, if you have any experiences about the water rates used in the eastern part of Germany - they might help too.

@Marcello: This already helps! Great!

Any source helps. If it's personal experience or recommendations or surveys -they are welcome.

More detail about my question:

Let our 10 treatments are one herbicide with variable doses along with one weedy check treatment in RCBD design. In weed dry matter, herbicide will have differential effect on different weed thus variable range of weed biomass and yield. But weedy treatment will have highest weed biomass with lowest yield. then if we compute LSD on the basis of these ten treatments, there will be statistical difference between weedy and herbicide effect. But the fine difference between effects of variable dose of herbicide will be missing. In that case if we opted for functional analysis, ANOVA of treatment effect will be split into two: herbicide v/s weedy and within herbicide doses.

then effect will be more clear?????

I have experienced a special designed syringe but for trunk injection. You can download in Researchgate: CALZARANO F., DI MARCO S., CESARI A., 2004. Benefit of fungicide treatment after trunk renewal of vines with different types of esca necrosis. Phytopathologia mediterranea, 43, 116-123. ISSN: 0031-9465.). The main problem was to relate the pressure of the plant with the pressure of the injection. In our case the syringe can "fit" their injection pressure to the plant in order to make possible the entrance of the fungicide 

Interesting question, to add some more for the above answers, First you have to know the actual active age of the culture you want to inoculate. Here what we do working with bacterial wilt of rice. Culture the bacteria for 48 hrs and then using a double distilled water (ddH2O) wash the plate and collect in a flask. Shake the mixture using a magnetic stirrer  untill it completely dissolves. Then measure the concentration using spectrometer at OD600. for our case, we use OD=78 because this is the concentration that can show difference between resistance and susceptible varieties but if  it is more than this any plant even non-host once do also show susceptibility.

Therefore, before you do any actual experiment to decide pathogenic. Identify which culture age to use, measure the concentration, determine the concentration and amount to inoculate, decide which age and part of the plant to inoculate. Then once you already standardize those  methods then you can also measure the CFU/ml for the OD level you use.

Hope this will give you some directions. Good luck

Try to create a near natural habitat inside your green house at some point.  It is easy in a tray or shallow cement tank and put soil from the place where you see this plant growing well.  We have successfully tried this in our Garden where we grow many water plants in pots and tanks. 

Hi,

for more information please find thes articles and websites. Maybe its can help you.

Under normal circumstances a resistant host will show a HR reaction whereas a non-host will show no such reaction.

Hi Grace,

I think your suggestion is good.

You can use the term damping off

Thanks!

Plant parasitic nematodes, especially virus vectors obtained in Vicia faba will show in article( in press). Some aspects of fungi parasiting nematodes are discussed.. By the way, I ask in nematode faunistics surveys, in water plants from lakes and Baltic coast( Hirschmanniela sp) and nematodes Longidoridae and Trichodoridae as plant virus vectors  from Latvia.Greetings. Andrzej. Gdynia

 I have seen similar disorder in eggplant and pepper plants under field conditions. I am not sure about the cause. I wonder if it may be in part related to physical damage on the stem caused by the rope producing abrasion.

You seem to have a very good understand many of the limitations with visual phytotoxicity assessments. Additional problems include the issue of many researchers not doing this assessments blind (they take a plot plan with them and know what plots they are rating) so the potential for bias is VERY high. My question would be why use them at all? Because of these problems most journals will not allow publication of papers without additional truly quantitative data such as biomass and yield. Because of this we will use them sometimes as a semi-quantitative way of describing herbicide phytotoxicity but I am not sure of there utility for anything beyond that. However for those that are screening massive amounts of herbicide plots they may be a necessary tool. Looking at other disciplines that have done a better job may be informative - plant pathology in particular has been much more rigorous in there development of scales for plant pathogen symptoms.  This approach probably could be transferred to contact herbicides fairly well. The issue always will be that there are large differences between herbicide MOA and plant species. In addition for many MOA most obvious symptomatology is the cessation of plant growth that requires the comparison of the untreated plots with treated and therefore removes part of the blind rating. So is this impossible - no, but I think one has to consider if the data will really be that much better. 

Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew. nature biotechnology,2014,doi:10.1038/nbt.2969

I work with SVNV. We keep the plants in the dark overnight before inoculating in the morning. We use young plants. I combine mono and di-sodium phosphate in the buffer until the pH is 7.2. I use fresh buffer each time. Add 2-mercaptoethanol to phosphate buffer at 0.1% rate. use this buffer to grind the plant tissue and apply to leaves (that have been dusted with carborundum) gently with gloved finger. Keep buffer and plant tissue cold throughout process. then rinse leaves after a couple minutes. 

With SVNV we only get about a 25% success rate, so I inoculate many plants at a time. It also appears that there may be variations between strains. Maybe this is happening with your virus. 

dear ahmed,

the reason this time is that the sun rays are entering perpendicular to the planet earth, a situation that allows for greater reliability in the determination of temperature without wome can determine the best time of reading, performing a temperature curve along the day and based on this information to determine the optimal range for determination, added to a correlation with parameters of gas exchange.

Dear András,

In total the area of peach orchards is about 584 ha but peaches are frequently grown in gardens.

The occurence of secondary pests in Bt crops and the underlying mechanisms were described in the following papers:

Hagenbucher, S., Wäckers, F.L., Wettestein, F.E., Olson, D.M., Ruberson, J.R., and Romeis, J. (2013). Pest tradeoffs in technology: Reduced damage by caterpillars in Bt cotton benefits aphids. Proc. Roy. Soc. B 280: 20130042. http://dx.doi.org/10.1098/rspb.2013.0042  

Faria, C.A., Wäckers, F.L., Turlings, T.C.J. (2007). Increased susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests. PLoS ONE 7

Dear Prof. Shashikant S. Udikeri,

Cotton and cucumber are two wholly different crops. I do not think that the economic threshold value calculated for cotton will work on cucumber.

While not being aware of any studies I am aware that portable electric fence technology has been used. A New Zealand Company Gallagher manufacture a range of products for animal management . Contact them directly  http://www.gallagher.co.nz/