Σάββατο, 28 Ιουλίου 2018

ΠΑΤΑΤΑ: Έλλειψη καλίου


κάντε κλικ επάνω στις φωτογραφίες








Δορυφόρος της Πατάτας












Ζημιά από Ζιζανιοκτόνα σε Πατάτα


Herbicide Injury in Potatoes

Herbicide injury in potato not only can reduce yield, but potato quality often is compromised. Contact herbicides can disrupt the growth of potato plants, causing potatoes to become malformed. Systemic herbicides will travel to the growing points - the newest leaf grow and the tubers. When most herbicide residues are found in the tuber they cannot be sold for food or feed. These translocating herbicides stored in seed potato tubers can also cause negative effects when the seed tubers are planted the following growing season. Common herbicides types that translocate causing problems in potato are glyphosate, plant growth regulators and ALS-inhibiting herbicides. 


robinson.1

robinson.2

NDSU/U of M Extension Potato Agronomist

(07/26/18)







ΕΛΙΑ: Δειγματοληψία φύλλων για προσδιορισμό θρεπτικών στοιχείων


https://drive.google.com/file/d/1_DmaqXXFX4-yq9ZC31SMvy7DcInI9uhz/view?usp=sharing

ΑΓΡΟΤΙΚΟ ΙΝΣΤΙΤΟΥΤΟ ΚΑΛΑΜΑΤΑΣ







ΑΝΑΛΥΣΗ ΦΥΤΙΚΩΝ ΙΣΤΩΝ. Μία διαδικασία άκρως απαραίτητη στην θρέψη των φυτών



Plant tissue analysis: An important part of nutrient management

Need a report card on your fertilizer program or diagnosis of a nutrient deficiency? Plant tissue analysis is your answer!


Potassium-deficient soybeans.

Potassium-deficient soybeans. Photo by Mike Staton, MSU Extension

Plant tissue analysis is determining, in a laboratory, the total elemental content of the whole plant or parts of plants, typically leaves or petioles (leaf stem). In field crops, plant tissue analysis, in conjunction with a soil test program, can serve as a check on a fertilizer program. Plant tissue analysis can also serve as a trouble shooting tool to diagnose a suspected nutrient deficiency.
Plant tissue analysis as a check on a fertilizer program

Plant nutrient levels can vary depending on the growth stage of the plant. Therefore, when taking plant samples for analysis as a check on a fertility program, the plant growth stage at sampling is important. Also, the nutrient levels can vary from one part of the plant to the other. Plant nutrient sufficiency levels have been calibrated to certain growth stages and parts of the plant.

See the following table for sampling time and plant part to be sampled for corn, wheat and soybeans, according to “Secondary and Micronutrients for Vegetables and Field Crops,” Michigan State University Extension bulletin E486.

Recommended sampling time and part of plant for five field crops
Crop
Sampling time
Plant part
Corn
Initial silk
Ear leaf
Wheat
Prior to initial bloom
Upper leaves
Soybeans
Prior to initial flowering
Upper fully developed leaf
Alfalfa
Prior to initial flowering
Top 6 inches
Sugarbeets
Mid-season
Center fully developed leaf

For crops not noted above, generally collect the upper fully developed leaf prior to the reproductive stage or mid-season. The table below reports the sufficiency ranges, in percentage, of dry weight for primary and secondary nutrients, according to “
Secondary and Micronutrients for Vegetables and Field Crops.”

Sufficiency ranges of N, P, K, Ca, Mg and S for five field crops
Crop
N (%)
P (%)
K (%)
Ca (%)
MG (%)
S (%)
Corn
2.76 – 3.50
0.25 – 0.50
1.71 – 2.50
0.21 – 1.00
0.16 – 0.60
0.16 – 0.50
Wheat
2.59 – 3.00
0.21 – 0.50
1.51 – 3.00
0.21 – 1.00
0.16 – 1.00
0.20 – 0.40
Soybeans
4.26 – 5.50
0.26 – 0.50
1.71 – 2.50
0.36 – 2.00
0.26 – 1.00
0.21 – 0.40
Alfalfa
3.76 – 5.50
0.26 - 0.70
2.01 – 3.50
1.76 – 3.00
0.31 – 1.00
0.31 – 0.50
Sugarbeets
3.01 – 4.50
0.26 – 0.50
2.01 – 6.00
0.36 – 1.20
0.36 – 1.00
0.21 – 0.50


As you can see, while the sufficiency levels are generally consistent between nutrients, especially phosphorus (P) and potassium (K).
When collecting plant tissue samples, it’s important to get a representative sample across whatever area you are sampling. Like a soil sample, collect in a zig-zag pattern. Collect at least 25 leaves, one leaf (or two in the case of wheat) from each plant, randomly across the entire area.
When analyzed, the plant tissue analysis can confirm the adequacy of nutrients or identify the inadequacy (or less often toxicity) of one or more nutrients.

Plant tissue analysis to diagnose a suspected nutrient deficiency
When a grower has a problem area in the field and a nutrient deficiency is suspected, plant tissue analysis can be used to help determine the problem. In this case, four samples should be taken—one soil sample from the problem area, one soil from an adjacent “good” area, one tissue sample from the problem area and one tissue sample from the good area. This approach should identify the cause of the problem if the problem is nutritional in nature.

Whether testing as a check on a fertility program or diagnosing a nutrient deficiency, take care in getting the samples delivered to the lab quickly so the sample does not mold. If you live within a reasonable driving distance of the lab, deliver them yourself or have a family member or employee deliver them for you. For most, however, a mail or package delivery service must be used. You can lay the samples in the sun for an afternoon to dry them down somewhat.

Send the samples on a day where they will not sit in transit over the weekend. That is, they should be mailed on a Monday, Tuesday or Wednesday if delivery can be assured by Friday. Samples should be placed in paper, not plastic bags, so the sample can “breathe.” The laboratory can refuse to test moldy samples.

This article was published by Michigan State University Extension





Ελμινθοσπόριο & Οστρίνια στον Αραβόσιτο


Ελμινθοσπόριο 

https://drive.google.com/file/d/1jOjpBdxgILQ10Jy4a24-hPlmUfPDXJaU/view?usp=sharing

πηγη: ΔΑΟΚ ΔΡΑΜΑΣ



Οστρίνια







πηγη: wikipedia & NDSU






Βακτηριακή προσβολή φύλλου φασολιάς





πηγη: NDSU





Σκωρίαση Φασολιάς


Dry Edible Bean Rust

Frequent dews and moderate-warm temperatures provide a favorable environment for dry edible bean rust. Rust is capable of causing yield loss, especially when it first occurs in the early to middle of the growing season. However, rust can be managed with fungicides and scouting for the disease is encouraged.

Signs and Symptoms. Dry bean rust is usually first found on the lower leaves of bean plants in ‘hot spots’, which are clusters of plants with relatively severe damage (Figure 1). Hot spots are often small (a few feet to several yards in diameter) and can occur anywhere in a field, but they are more common near shelter belts or last year’s   residue. Rust is usually first observed on the upper sides of the leaves and appear as dusty cinnamon-brown pustules that may be surrounded by a small yellow halo (Figure 2). Pustules on the undersides of the leaves may appear more robust and lack the yellow halo (Figure 3).

markell.1


markell.2

markell.3

Management. Dry edible bean rust can cause significant yield loss when the disease occurs early in the growing season and conditions remain conducive for infection and spread. A hot-spot can turn into a full-blown epidemic in just a couple weeks. The best timing for a fungicide application to manage rust is shortly after it is first found. QoI fungicides [strobilurins: FRAC 11] (Headline, Quadris and generics, Aproach, etc.), DMI fungicides [Triazole: FRAC 3] (Proline, Quash, tebuconazole generics, etc.) and mixtures containing these products (Priaxor, Propulse, etc..) have been the most efficacious in our trials. Fungicides with other modes of action, some of which are more commonly applied for white mold (Endura, T-methyl, etc..), have still reduced disease severity but often not as much as QoI and DMI chemistries. Exceptions have occurred.


Extension Plant Pathologist, Broad-leaf Crops

Σάββατο, 21 Ιουλίου 2018

ΕΛΓΟ, πρόγραμμα για νέες ποικιλίες


ΚΑΠΟΥ ΔΙΑΒΑΣΑ

Την Τετάρτη 18 Ιουλίου πραγματοποιήθηκε συνάντηση του Υφυπουργού Αγροτικής Ανάπτυξης και Τροφίμων κ. Βασιλείου Κόκκαλη, με τον Γενικό Γραμματέα κ. Νικόλαο Αντώνογλου, τον Πρόεδρο του ΕΛΓΟ ΔΗΜΗΤΡΑ κ. Νικόλαο Κατή, τον Γενικό Διευθυντή Οικονομικών Υπηρεσιών κ. Δημήτριο Τσαγκαλίδη και τους υπαλλήλους τηςΔιεύθυνσης Πολλαπλασιαστικού Υλικού Καλλιεργούμενων Φυτικών Ειδών και Φυτογενετικών Πόρων.

Κατά τη διάρκεια της συνάντησης συμφωνήθηκαν οι λεπτομέρειες για την επικείμενη έναρξη του προγράμματος δημιουργίας νέων ποικιλιών φυτικών ειδών. Με αυτό τον τρόπο αποδείχθηκε έμπρακτα η προτεραιότητα του Υπουργείου να ενεργοποιήσει για πρώτη φορά το άρθρο 9 του ν. 1564/1985, όπου προβλέπεται η λήψη μέτρων, για Ερευνητικά Προγράμματα με αντικείμενο την δημιουργία νέων ποικιλιών στον τομέα της φυτικής παραγωγής.


ΚΑΙ ΘΑ ΗΘΕΛΑ ΝΑ ΡΩΤΗΣΩ:

Τι έγιναν όλες αυτές οι ποικιλίες που δημιουργήθηκαν στο παρελθόν;;;

Τι απέγιναν τα καταπληκτικά υβρίδια αραβοσίτου ΑΡΙΣ, ΑΘΗΝΑ ΔΙΑΣ κλπ;;;;

Η δημιουργία υβριδίων και νέων ποικιλιών δεν είναι παιξε γελασε, χρειάζεται οργάνωση και προγραμματισμό και μετά αξιοποίηση. ΤΙ ΑΠΟ ΟΛΑ ΑΥΤΑ ΘΑ ΚΑΝΕΤΕ;

Ακόμα 1,5 εκατ ευρώ για πέταμα, μάλλον για απασχόληση σε μερικούς ερευνητές και διοικητικούς και εργατοτεχνίτες.

Εκτός και αν εξυπηρετεί κάποιον άλλον σκοπό.







Διαγωνισμός για τον καλύτερο νέο αγρότη του 2018

Αρσενικό σε ρύζι στην ελληνική αγορά;


Επιστολή «βόμβα» από τους Παιδίατρους της Αττικής: 

Στοιχεία που θα βοηθήσουν στην ενημέρωση και τη διαφύλαξη της υγείας των καταναλωτών σχετικά με την κυκλοφορία στην ελληνική αγορά προϊόντων με ρύζι με ανόργανο αρσενικό ζητά η Ένωση Ελευθεροεπαγγελματιών Παιδιάτρων Αττικής με επιστολή της προς τον ΕΦΕΤ.

Σύμφωνα με τον πρόεδρο της Ένωσης, Κώστα Νταλούκα, δημοσιεύτηκαν πρόσφατα στη διεθνή ιατρική βιβλιογραφία μελέτες για τον κίνδυνο που υπάρχει για την δημόσια υγεία, κυρίως για τα βρέφη και τα Περιγραφή: https://my.crazynapo.com/scripts/5u6i7la?a_aid=grothia&a_bid=052db4a3μικρά παιδιά, από την κατανάλωση ανόργανου αρσενικού που βρίσκεται στο ρύζι και στα προϊόντα ρυζιού, καθώς και ότι η Ευρωπαϊκή Ένωση θέσπισε ανώτατα όρια ασφαλείας όσον αφορά τον καθορισμό μέγιστων επιτρεπτών επιπέδων ανόργανου αρσενικού σε τρόφιμα.

«Με δεδομένους τους κινδύνους από το ανόργανο αρσενικό, που περιέχεται στο ρύζι και τις παιδικές τροφές ρυζιού αν αυτό ξεπεράσει τα επιτρεπόμενα όρια», οι παιδίατροι ζητούν να ενημερωθούν για τους ελέγχους που έχουν γίνει, προκειμένου να ενημερώσουν με τη σειρά τους γονείς.

-----------------------------------------

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Η Ένωση Ελευθεροεπαγγελματιών Παιδιάτρων απευθύνει τα εξής ερωτήματα προς τον ΕΦΕΤ και το υπουργείο Υγείας:

1. Γίνονται και κάθε πότε, δειγματοληπτικοί έλεγχοι στο ρύζι και στα προϊόντα ρυζιού σε σχέση με τα όρια που θέσπισε η Ευρωπαϊκή Ένωση όσον αφορά το ανόργανο αρσενικό;
2. Πότε έγινε ο τελευταίος δειγματοληπτικός έλεγχος;
3. Ποια ήταν τα αποτελέσματα;
4. Σε ποια προϊόντα έγινε;
5. Ισχύει σήμερα ο νέος κανονισμός της Ευρωπαϊκής Ένωσης;
6. Αν ισχύει υπάρχουν σήμερα στην Ελληνική αγορά προϊόντα ρυζιού και βρεφικές τροφές ρυζιού τα οποία δεν έχουν συμμορφωθεί με τον κανονισμό της Ευρωπαϊκής Ένωσης;
7. Είναι υποχρεωτικό για τις εταιρείες παιδικών τροφών ρυζιού να αναφέρουν στην ετικέτα του προϊόντος τα επίπεδα του περιεχομένου ανόργανου αρσενικού, ώστε να το γνωρίζει ο καταναλωτής;
8. Ποια πρέπει να είναι η συμπεριφορά του καταναλωτή και τι πρέπει να αναζητά στα τυποποιημένα προϊόντα, ώστε να είναι σίγουρος για την υγεία την δική του και των παιδιών του;
Οι παιδίατροι ζητούν, επίσης, οποιοδήποτε άλλο στοιχείο θα βοηθήσει στην ενημέρωση και την διαφύλαξη της υγείας των καταναλωτών, με ιδιαίτερη έμφαση αυτής των βρεφών και των μικρών παιδιών.

Επιστολή «βόμβα» από τους Παιδίατρους της Αττικής: Αρσενικό σε ρύζι στην ελληνική αγορά;
ΠΗΓΗ







Συμπτώματα σε φύλλα από προσβολή με Τετράνυχο




πηγη: U of Delaware






Μαργαρόνια κ Ακάρεα Eriophyidae στην Ελιά


Φωτογραφίες με το έντομο αλλά και με συμπτώματα.

https://drive.google.com/file/d/1Z496qUWcOuuzuBVQaEVod-aRw2BEuk4V/view?usp=sharing








Τοξικότητα Μαγγανίου σε Πεπόνια


Symptoms: Symptoms of manganese toxicity usually appear on older leaves of cantaloupe when fruit begin to net or when fruit are the size of billiard balls and there have been heavy rains. The worst symptoms appear shortly before harvest and in lower areas of the field. The best way to determine whether you have Mn toxicity is to take an affected leaf and hold it up to the sun. Tiny pin-hole sized lesions with yellow halos clustered between the veins will be visible (Fig. 1). As the lesions mature, they will coalesce, and turn brown (Fig. 2). Some cantaloupe rows often seem to be worse than adjacent rows. Affected plants frequently appear as clusters in the field. Moderately to severely affected cantaloupe plants will demonstrate poor vegetative growth and reduced or incomplete fruit maturation. The combination of all these symptoms often can be confused with several infectious diseases. Because of the symptoms growers will at times increase their fungicide sprays, which may lead to phytotoxicity problems.


Figure 1. Pin-head lesions surrounded by a halo of yellow or clear tissue.


Figure 2. Younger leaves with pin-hole lesions (red) and older leaves with pin-hole lesions coalescing to form larger necrotic areas (black).

Cause: Manganese toxicity is caused by soil pH levels that are at or below 5.8. Excess soil acidity allows manganese that is normally bound to soil particles to be released and taken up by the plant in very high concentrations, i.e., toxic levels. Manganese levels of 800-900 ppm and above in foliar tissue is usually toxic. Losses to manganese toxicity can be severe. The apparent “spread of the disease” is due to plants in the field where pH is lower developing symptoms first and plants in areas where the pH is not as low developing symptoms days or even weeks later. Growers may have had their soil tested and had spread lime in the fall but still have this problem—low pH in some parts of the field.

One of the reasons for the drop in pH even though lime has been applied is the use of pH lowering fertilizers such as ammonium and urea. These acidifying fertilizers can have a long-term effect on soil that is cumulative and leads to lower pH levels. Ammonium sulfate, (NH4)2 SO4, can significantly lower pH, while ammonium nitrate (NH4NO3) and dried blood make soil moderately more acid, and urea makes soil only slightly more acid. Ammonium is made up of nitrogen and hydrogen and over time is converted to nitrate by soil bacteria, the warmer the soil, the faster the conversion. During the conversion to nitrate, nitrogen loses hydrogen and adds oxygen. The hydrogen ions are free in the water solution between soil particles to react with various substances. Plants have difficulty obtaining the nutrients they need in the proper amounts when the soil water solution has too many hydrogen ions (low pH).

Symptoms of Mn toxicity are worse when there are heavy rains because of the lack of soil oxygen, which results in changes in the availability of some nutrients like manganese. Under saturated soil conditions manganese is made more readily available to plants and in low pH soils the likelihood of manganese toxicity increases.

Magnesium (Mg) deficiency is also a possibility when pH levels drop below 5.8. In this case plants do not take up enough of the nutrient. Deficient plants exhibit interveinal chlorosis (yellowing or scorching of leaf tissue between veins) with the veins remaining green (Fig. 3). If soils are acidic and low in Mg, dolomitic lime can be used in the fall or to help right now magnesium fertilizers can be used.

Prevention: Soil acidity levels should be maintained above a pH of 6.3. Soil tests on sandy soils need to be done every year, at least for pH levels. The pH levels can change even after one year on sandy, low organic matter soils. Lime should be mixed into the soil at least several months before planting. While many plants do not grow well in acidic soils, cantaloupe is especially sensitive to the lower pH levels. Watermelon will rarely show signs of Mn toxicity even at a low pH. There is little that can be done to correct for manganese toxicity during the season. However, using fertilizers with a nitrogen source of nitrate-nitrogen (calcium nitrate and potassium nitrate) instead of ammonium-nitrogen may help increase soil pH. Potassium carbonate also can raise soil pH. It is water soluble and can be applied through drip systems. However, correcting soil pH can be an arduous and lengthy process and it’s probably too late to see a yield response in the current season if the symptoms have already been observed.



Figure 3. Magnesium deficiency in cantaloupe with interveinal scorching and veins that remain green.


Manganese Toxicity in Cantaloupes







Παρασκευή, 20 Ιουλίου 2018

Προσβολη σε φύλλα, καρπό κ βραχίονες σε Μηλιά από Botryosphaeria

Συμπτώματα σε φύλλο αραβοσίτου απο red-headed flea beetle (Systena frontalis)

Knodel.2 3




πηγη: NDSU




Brown Stink Bug Damage to Corn

Brown stink bugs are found throughout the world and are pests of many crops. 

Identification of Brown Stink Bugs

Spotted stink bug

Typically, it is brown stink bug species that attack corn. One of the most common of these is the spotted stink bug, Euschistus variolarius . This insect is brown in color and approximately 7/16 inch (9 mm) in length when fully grown. Adults are broad, somewhat flat, and shield-shaped. The upper side of the body ranges from light to very dark brown. The underside varies from light yellow to green.

Crop Damage
Stink bugs feed by inserting their needle-like mouth-parts into plant tissues, injecting materials into the plant to aid in digestion, and sucking out plant juices. This feeding damages the plant physically, much like stabbing plant tissues repeatedly with a fine needle, leaving a tattered or shabby appearance. Feeding also damages plants chemically, because the materials injected by the insect are toxic to the plant. This damage is manifest as yellowing, twisting and stunting of leaves and stalks of corn seedlings (Figure 1).

Brown stink bug damage to corn plant.

Figure 1. Brown stink bug damage to corn plant.

Injury due to stink bug feeding may range from moderate to severe to lethal, depending on the extent of infestation and which tissues are affected. Leaf and stalk feeding may result in modest or severe stunting, but damage to the growing point may kill the plant. When growing point damage occurs, tillers or "suckers" may be produced from lateral meristems at the base of the plant. There is typically a row of oval holes with yellow borders across the unwrapped leaves of damaged plants. This row results from the single feeding puncture that penetrates the wrapped leaves. A slimy, decaying area may be found in the stalk where the stink bug has fed. This is most likely an effect of the insect's digestive juices.


Damaged corn leaf with oval holes and yellow borders.


Corn plant tillering caused from stink bugs.

Tillering is the most dramatic symptom of damaged plants. Tillering usually first appears about 10 days after the damage was caused. A shoot or tillers begin to grow from the base of the plant and may become as large as the original plant. Damaged plants may develop misshapen ears on tillers in place of the tassel.
The primary corn ears can also be damaged by later feeding of brown stink bugs. If a stink bug pierces into a developing ear it will typically be curved or bent from the point of feeding (Figure 2).


Curved corn ears due to brown stink bug adults.


Tillage and Cropping System Influence
Figure 2. Corn ears are curved due to piercing of the developing ear by brown stink bug adults¹.

Stink bug damage is most severe in no-till fields. In some no-till situations, damage can be found throughout the field, often with areas of very intense damage. Frequently, the most impacted portions of the field are near wooded areas. Stink bug damage can be found in conventional-till fields, but the incidence is usually low and often limited to the border rows. A soybean-wheat-corn cropping sequence can be especially favorable for stink bug damage. A stink bug population can build up in soybeans during podfill. Wheat cover crops provide an attractive early spring host for the insects, and subsequently they feed on emerging corn. The stink bugs may overwinter in the wheat stubble, or they may leave the field for over- wintering sites and return in the spring.

Yield Loss
Stink bug injury to corn can reduce yields in several ways - stunted plants yield less, and plants with injury to the growing point may die or produce tillers, both of which reduce yields. Stunted plants usually outgrow stink bug feeding damage and may catch up in height with undamaged plants in two to four weeks. However, research at the University of Kentucky indicates that yield from these plants will be reduced about 10% on average. Growing point injury may reduce stands below the optimum, thus lowering yield. Another effect of this injury is tillering ("suckering") by the plant. Tillered plants may produce little if any grain. Some may produce small ears with about one-third the yield of undamaged plants. In some cases the ear forms where the tassel normally appears. Tasseling and silking of these plants may be delayed a week or more. Tillered plants may in effect become weeds, growing to a height of several feet and competing for water and nutrients with undamaged plants.


Small ears with reduced yield caused by brown stink bugs.

Management

Economic thresholds are not established for brown stink bugs in corn in most states. However, grower experience has shown that insecticides are most effective when applied prior to or at plant emergence.Management
Scouting for stink bug damage is difficult and must be done very early to be effective. The first two weeks following corn emergence are critical for scouting. Scout as you would for cutworms, but in addition to cutworms and their damage (cut plants), look for stink bugs and their damage. Stink bugs tend to feed at the base of corn plants, usually an inch above the soil surface.
Special attention should be given to these fields:
fields that are no-tilled
fields infested with winter annual weeds
fields with a history of stink bug injury.


Always read and follow label directions when applying insecticides.
1Image source: the Ohio State University Northwest Agricultural Experiment Station, 2008.

πηγη

https://www.pioneer.com/home/site/us/agronomy/library/brown-stink-bug-corn/                                                                                                                    Field Facts written by DuPont Pioneer Agronomy Sciences






Συμπτώματα σε φύλλα αραβοσίτου από Ημίπτερα




πηγη: U of Delaware

Συμπτώματα σε φύλλα αραβοσίτου μετά από νύγματα απο ημίπτερα και συγκεκριμενα:
the green stink bug, Acrosternum hilare, and brown stink bugs, Euschistus spp.






Ιωσεις σε φύλλα τομάτας





πηγη: U of Delaware





Τετράνυχοι σε φύλλα καρπουζιάς





πηγη: U of Delaware








Ανθράκνωση κ Σκληρωτίνια σε Φακή





πηγη: NDSU





Παρασκευή, 13 Ιουλίου 2018

Οι αγρότες «πεθαίνουν» … μόνοι …


ΑΓΡΟΝΕΑ ΜΙΧΑΗΛΙΔΗΣ

ΑΝΤΑΠΟΚΡΙΣΗ 9 Ιουλίου 2018  
Οι αγρότες «πεθαίνουν» … μόνοι … 

Συνεχίζουμε αμήχανα να καταγράφουμε τους θανάτους αγροτών από ατυχήματα. Πόσοι εργαζόμενοι στον αγροτικό τομέα σκοτώνονται και τραυματίζονται στην Ελλάδα? Μήπως ο αριθμός είναι πάρα πολύ μεγάλος? ΓΙΑΤΙ ΔΕΝ ΑΣΧΟΛΕΙΤΑΙ ΚΑΝΕΙΣ ΜΕ ΑΥΤΟ ΤΟ ΠΡΟΒΛΗΜΑ? Γιατί δεν το μελετά κάποια πτυχιακή στα Πανεπιστήμια? Γιατί δεν χρηματοδοτούν έρευνες τα ποικιλώνυμα Ιδρύματα? Γιατί δεν απασχολεί τον ΕΛΓΟ ΔΗΜΗΤΡΑ?. Γιατί δεν προωθούνται κάποιες Διδακτορικές διατριβές. Μήπως πληρώνουν κάποιοι όσους ΔΕΝ ασχολούνται με αυτό το θέμα? … Είναι κομμάτι του άτυπου «πολέμου» των αστών εις βάρος των αγροτών, για να αποκτήσουν οι αστοί «ζωτικό» χώρο επιβίωσης? …

Και τα παραπάνω μόνο με αφορμή τα ατυχήματα που μαθαίνουμε όλοι οι πολίτες. Τι γίνεται με τις αγροτικές επαγγελματικές ασθένειες? Μπορεί να διασταυρωθεί αν η χρήση φυτοφαρμάκων αυξάνει τα κρούσματα (θάνατοι) από διάφορους καρκίνους? Πώς επιδρά το περιβάλλον, ο έντονος ήλιος, η μεγάλη διάρκεια δουλειάς, η συνεχής διαθεσιμότητα για δουλειά 365 μέρες το χρόνο, χωρίς διακοπές, στην ψυχική υγεία του αγρότη? Περιέργως κανένας δεν ασχολείται ή δεν θέλει να ασχοληθεί ή δεν προλαβαίνει να ασχοληθεί, διότι άλλες εργασίες είναι πιο ελκυστικές, ίσως και προσοδοφόρες … με τα αγροτικά ατυχήματα, και τις αγροτικές επαγγελματικές ασθένειες.

Αλτερνάρια, Ανθράκνωση, Περονόσπορος & Ωίδιο σε Κολοκυνθοειδή

Κερκόσπορα σε Ζαχαρότευτλα και Προσπάθειες Ελέγχου


Managing Cercospora Leaf Spot of Sugarbeet

Cercospora leaf spot (CLS) (Figure 1) is the most destructive foliar disease of sugarbeet in North Dakota and Minnesota.  The causal agent of CLS is the fungus Cercospora beticola, which is most damaging in warm weather (day temperature of 77 to 90° F and night temperature above 60° F) and in the presence of moisture from rain or dew on the leaves for 8 or more hours. The fungus destroys the leaves and adversely impacts photosynthesis. The longer and more severe the infestation, the greater the reduction in tonnage, sugar concentration and recoverable sucrose. Roots of CLS infected plants have higher impurities and are more costly to process. 

khan.1

Growers typically mange CLS by integrating rotation with non-hosts crops including corn, soybean and wheat, planting CLS tolerant varieties, planting away from a previously infected crop, and applying fungicides in a timely manner. 
The CLS epidemic of 2016 (Figure 2) has resulted in a C. beticola population that is highly resistant to QoI fungicides (Headline, Priaxor, Gem) and has also become less sensitive to triazoles (Eminent, Minerva, Inspire XT, Proline, Enable, Topguard), triphenyltin hydroxide (TPTH) (Super Tin, Agri Tin), Thiophanate methyl (Topsin). As a result, the efficacy of individual fungicides to control C. beticola has been significantly reduced in most instances.

Ανθράκνωση, Ωίδιο κ Σεπτόρια στην Κρανιά

Προσβολή σε φύλλα Βούξου απο Cylidrocladium

Τετάρτη, 11 Ιουλίου 2018

CITRUS HUANGLONGBING (HLB) or CITRUS GREENING


Φωτογραφίες


πηγη: J. W. Lotz


πηγη; Canales et al 2016



ΑΙΤΙΟ - ΠΕΡΙΓΡΑΦΗ

Candidatus Liberibacter asiaticus

Class: Alpha Proteobacteria
Order: Rhizobiales
Family: Phyllobacteriaceae 


Candidatus Liberibacter asiaticus

Photographer: Hilda Gomez Affiliation:USDA



Candidatus Liberibacter asiaticus

Photographer:ME Rogers Affiliation: University of Florida Source

DESCRIPTION

Huanglongbing (HLB) in Chinese literally translates to “Yellow Dragon Disease” and it is caused by phloem-limited bacterium. That means that this bacterium attacks the phloem system of plants which is like the circulatory system in animals. Leaves of newly infected trees develop a blotchy mottle appearance. On repeatedly infected trees, the leaves are small and exhibit asymmetrical blotchy mottling. Fruit from HLB-infected trees are small, lopsided, poorly colored, and contain aborted seeds. The juice from affected fruit is low in soluble solids, high in acids and abnormally bitter. The fruit retains its green color at the navel end when mature, which is the reason for the common name "citrus greening disease." This fruit is of no value because of poor size and quality.


Δευτέρα, 9 Ιουλίου 2018

Κρίσιμη για την Παραγωγή η Ορθολογιστική Χρήση του νερού


Τα κρίσιμα στάδια σε τέσσερις δενδρώδεις καλλιέργειες 

https://drive.google.com/file/d/1ZaA69qHWnZ0dtwbQhSQg-Y3DJ74fJztj/view?usp=sharing







Πσοσβολή από Phomopsis σε Άρκευθο

Γνωριμία με την (τον) Σκληρωτήνια


Review of conditions favorable for white mold     

As broadleaf crops enter bloom they can become susceptible to white mold infection.
However, many factors will help determine how much of a concern white mold will be in field, including; temperature and canopy wetness during bloom, disease history, canopy density and variety susceptibility. As a result, assessing your risk for white mold is very important in managing the disease.

A good understanding of how white mold works will help make management decisions. The information below may help you get your head wrapped around white mold!

How does white mold occur?
Sclerotinia survives in the soil as sclerotia; hard, black structures (figure 1). When there is ample soil moisture, at least 1 to 2 inches of water a week or two before bloom, the sclerotia will germinate, produce apothecia (little mushrooms) and release ascospores (Figure 2).  

Once spores are released, they need to land on a nutritional source to begin the infection process; usually the flower petals. Once the flower petals become colonized, the pathogen easily penetrates the plant (Figure 3) and produces the characteristic light tan / white lesion (it looks like dry bone), takes on a shredded appearance, and black sclerotia are produced (figure 4).

markell.1 2


markell.3



markell.4

What are favorable conditions for white mold?

Broadleaf plants become susceptible to white mold only once they begin blooming (sunflowers are an exception). This is because the pathogen needs to utilize the flowers as a food source to cause infection.
Soils need to be moist before bloom. Generally, 1-2 inches of rain falling in a 1-2 week period before plants enter bloom is the minimum needed for sclerotia to germinate, produce apothecia, and release ascospores.
Moderate temperatures and wetness during bloom. High temperatures above 85 degrees F inhibit disease. In years where we hit the 90’s F consistently during bloom, we rarely have white mold. Sclerotinia infection and development is best when daytime highs are cooler; 60’s- 70’s.

The canopy needs to be wet. Rain, fog, and heavy dews during bloom are all favorable for disease. Paying attention to the long term rain forecast is important if deciding to make a fungicide application.
Canopy density and canopy closure make a big difference on the environment in the field. Once canopy closure occurs, the crop is likely to have a more favorable environment for infection and disease development.
Field history can make a difference. Some fields that have a history of white mold, may be more likely to have future epidemics. Importantly, we are taking about field history over long periods of time. Remember, the sclerotia can survive for many years in a field, so an epidemic three years earlier may still be influencing this year’s growing season. Consequently, just because we had a drought last year doesn’t mean we won’t have disease.

Crop rotation makes a difference. A field with a history or white mold and short rotations among broadleaf crops is more likely to have white mold problems than a field with no white mold history and/or long crop rotations.

Crop makes a difference. Not all broadleaf crops are equally susceptible to white mold. Sunflowers and dry edible beans consistently seem to be very susceptible, and little resistance is available. Similarly, canola can be hit hard when the environment is favorable. Soybeans can be infected, but they typically do not experience the yield loss the other crops do. Additionally, some varieties of soybean are much less susceptible to white mold than others. Peas can get white mold, but it is less common than other crops.

How do you manage white mold with fungicides?
Fungicides can help manage the disease and on some crops they can be very effective. Dry bean applications can be very beneficial in favorable environments; canola application can be as well. Fungicide applications to soybeans are more variable however and favorable economic returns are less common. Part of the reason is soybeans are naturally less susceptible that dry beans or canola. Sunflower is very susceptible to white mold, but fungicides are not recommended because they are generally not effective at reducing disease.
If you choose to make a fungicide application, timing is very important. Applications made relatively early in the bloom stages are preferred because it helps manage infections that can occur right after the plant enters bloom. In some cases, canopy closure is a very important consideration that may alter timing strategy slightly. The early infections tend to do the most damage because they have the greatest time to develop through the season. Later applications may also prevent infections, but those later infections do less damage.  
Many fungicides are available that have efficacy against white mold. Selection of them will depend on crop, efficacy (which can vary some by crop) and price.


What resources are available?
The canola sclerotinia risk map uses environmental conditions favorable for sclerotinia, so it can be helpful for all broadleaf crops. http://www.ag.ndsu.edu/sclerotinia/
Colorado and Nebraska have developed a fungicide decision checklist for dry beans, found at http://extensionpublications.unl.edu/assets/pdf/g1786.pdf
Extension Plant Pathologist, Broad-leaf Crops