Pepper Plant Blight: Information For Controlling Phytophthora On Peppers

By Kristi Waterworth

The soil is full of living things, some useful, like earthworms, and others not as useful, like the fungi in the genus Phytophthora. These irksome pathogens can last long after infected plants have composted into nothing, continuing to attack plants at all stages of development. Knowing the signs of phytophthora pepper blight will help you head off disaster if this fungus appears in your garden.

Phytophthora Symptoms on Pepper Plants

Pepper plant blight manifests in many different ways, depending on what part of the plant is infected and at what stage of growth the infection set in. Many times, seedlings infected with phytophthora die shortly after emergence, but older plants usually continue to grow, developing a dark brown lesion near the soil line.

As the lesion spreads, the stem is slowly girdled, causing sudden, unexplained wilting and the eventual death of the plant – root symptoms are similar, but lack the visible lesions. If phytophthora spreads to the leaves of your pepper, dark green, circular or irregular lesions may form on the tissue. These areas quickly dry to a light tan color. Fruit lesions begin similarly, but blacken and shrivel instead.

Controlling Phytophthora on Peppers

Phytophthora blight in peppers is common in wet areas when soil temperatures are between 75 and 85 degrees Fahrenheit – these are ideal conditions for rapid multiplication of the fungal bodies. Once your plant has phytophthora pepper blight, there’s no way to cure it, so prevention is key. In beds where phytophthora has been a problem, crop rotation with brassicas or grains on a four year rotation can starve the fungal bodies out.

In a new bed, or after your crop rotation is complete, increase drainage by amending the soil heavily with compost, using as much as four inches on a 12 inch deep bed. Planting peppers on eight- to ten-inch tall mounds can further help to prevent the development of phytophthora. Waiting to water until the soil two inches below the surface feels dry to the touch will prevent over watering and deny phytophthora the conditions it needs to survive.

Source: http://www.gardeningknowhow.com

Biomin: EU gives positive votes for mycotoxin products

Biomin announces the positive votes of the EU Standing Committee on the Food Chain and Animal Health (SCFCAH) on the authorisation of two Biomin products as “substances for reduction of the contamination of feed by mycotoxins”.

Two products from the well-established Mycofix product line of Biomin, Mycofix Secure (bentonite/dioctahedral montmorillonite) and Biomin BBSH 797 (Gen. nov. sp. nov., formerly Eubacterium), are slated to become the first-ever products authorised by the EU as substances with proven mycotoxin counteracting properties.
Following the positive SCFCAH votes, the publication of the respective EU regulations would be the next and final stage towards confirming the scientific efficacy of Mycofix Secure and Biomin BBSH 797 as mycotoxin-deactivating products.
Biomin BBSH 797 is the first-ever product to receive this positive vote, thereby affirming its capability in the biodegradation of trichothecenes. The patented active bacterium in Biomin BBSH 797 modifies the structure of these mycotoxins, a biotransformation process that renders trichothecenes such as deoxynivalenol (DON) harmless. Making it a valuable feed additive for pigs, considered the species most susceptible to in-feed DON contamination.
Mycofix Secure is a bentonite (dioctahedral montmorillonite) that fulfills the strict requirements on aflatoxin-binding capability according to the European Union Reference Laboratory (EURL). In cooperation with the EURL, Biomin developed an analytical method to characterize the AfB1-binding capacity of bentonites which has now become a crucial part of the authorisation process for aflatoxin binders. These efforts spearheaded by Biomin have paved the way for legalising “aflatoxin-binding” as an official claim.
The process towards the authorisation of Mycofix Secure and Biomin BBSH 797 in the EU began when, on the initiative of Biomin, the EU Association of Specialty Feed Ingredients and their Mixtures, or FEFANA, established the Task Force “Mycotoxins” in 2005. In 2009, the Task Force succeeded in opening a new functional group for mycotoxin counteracting products, signifying a landmark development in the official approval of mycotoxin deactivating products within the EU. This led subsequently to the publication of stringent European Food Safety Authority (EFSA) guidance for anti-mycotoxin product registration—including proofs for mycotoxin and species specificity, efficacy and safety—which have generally deterred the industry from submitting dossiers for EU authorization of anti-mycotoxin feed additives.
In 2010, Biomin, however, became the first feed additive company to submit a dossier to legalise the claim of “aflatoxin-binding” properties (Mycofix Secure). This was followed in 2012 with a dossier for the “biodegradation of trichothecenes” (Biomin BBSH 797) for EU approval. After a thorough scientific evaluation process, Biomin became the first feed additive company to obtain positive opinions from EFSA on these technological feed additives capable of reducing the negative impacts of mycotoxins in animals.

Source: http://www.allaboutfeed.net

Establishing the Cause of Disease

Source: http://www.sciencemag.org/content/276/5313/726/F1.large.jpg

The correct diagnosis of a plant disease and its cause is not always an easy task. In the first instance symptoms may be ill defined which make their association with any organism problematic (Derrick and Timmer, 2000) and, secondly, plants grow in environments which are notably non-sterile. In particular, besides supporting a microflora on their aerial parts, the phylloplane, they are rooted in soil which may contain in excess of 1 million organisms per gram. The plant pathologist is therefore faced with trying to determine which, if any, of the organisms associated with the diseased plant is responsible for the symptoms. This is normally achieved by the application of the postulates of Robert Koch, a German bacteriologist of the 19th century, which for plant pathogens may be stated as follows:

1. The suspected causal organism must be constantly associated with symptoms of the disease.
2. The suspected causal organism must be isolated and grown in pure culture.
3. When healthy test plants are inoculated with pure cultures of the suspected causal organism they must reproduce at least some of the symptoms of the disease.
4. The suspected causal organism must be re isolated from the plant and shown to be identical with the organism originally isolated.

Clearly, these criteria can only be met with organisms that can be cultured, ruling out all obligate pathogens which include a number of important fungi, many phytoplasmas and all viruses and viroids. Establishing these organisms as causal agents of disease usually involves purification of the suspected agent rather than culture and the demonstration that these purified preparations reproduce at least some of the disease symptoms.
Reference: Introduction to Plant Pathology. Richard N. Strange. 2003. John Wiley and Sons Ltd.

Mollicutes (Phytoplasmas)

For nearly 70 years after viruses were discovered, many plant diseases were described that showed symptoms of general yellowing or reddening of the plant or of shoots proliferating and forming structures that resembled witches’ brooms. These diseases were thought to be caused by viruses, but no viruses could be found in such plants. In 1967, Doi and colleagues in Japan observed mollicutes, i.e., wall-less mycoplasma-like bodies in the phloem of plants exhibiting yellows and witches’ broom symptoms. That same year the same group showed that the mycoplasma-like bodies and symptoms disappeared temporarily when the plants were treated with tetracy-cline antibiotics. Since then, mycoplasma-like organisms (MLOs) that infect plants have been reclassified as phy-toplasmas, and some of them that have helical bodies and can be found in other environments besides plants are known as spiroplasmas.