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Thursday, January 23, 2014

Heirloom Tomatoes for SW Florida

Earlier this month, Dr. Monica Ozores-Hampton spoke to us on heirloom tomatoes.

Monica has done heirloom variety testing in South Florida. She recommends for us: Pruden's Purple, Cherokee Purple, Striped German, Brandywine, (Jaune) Flamme, Green Zebra, Amana Orange, and Big Zebra.

If she HAD to choose a favorite, it would be Cherokee Purple for its good-looking, EXTRA large tomatoes.

Monica also discussed Graywall (Blotchy Ripening). Here is a blurb on it from the UF/IFAS Publication #HS954:

Internally graywall is characterized by dark necrotic (death of cells or tissues through injury or disease) areas usually in the vascular tissue (a specialized conducting system) of the outer walls. The necrosis is sometimes present in the cross-walls and very infrequently in the center pith area of the fruit. Outward symptoms show up as grayish appearance caused by partial collapse of the wall tissue; hence the term graywall. It typically develops on green fruit prior to harvest but can develop later. Fruits affected are typically not marketable due to blotchy appearance as fruit ripens. Cause is not completely understood. There are variety differences in susceptibility. Graywall is more of a problem during cool and short days. High N may increase the problem and adequate K (Potassium) may reduce the problem. (Monica noted that the plant needed MORE Potassium than Nitrogen for fruit.)

Monica noted that she personally grows heirlooms in a greenhouse, in a one gallon pot, using 20-20-20 fertilizer.

Here is the link to Monica's document: "Growing Heirloom Tomato Varieties in SW Florida" that she handed out: http://edis.ifas.ufl.edu/hs174

This document lists the websites to obtain heirloom tomato seeds. Her personal favorite site is www.tomatofest.com.

Thursday, January 9, 2014

Citrus Canker Disease ID with PICTURES

Citrus Canker Disease

  • Found on both sides of leaf
  • Raised leisions
  • Sometimes holes in leaves
  • Juice from fruit is okay to drink
  • Mongi Zekri Ph.d UF/IFAS 5-County Agent

  • Most infections occur between April and July on oranges
    Three to four applications of copper-containing materials at 3-week intervals should be sufficient to obtain relatively clean fruit. 
  • Grapefruit are susceptible to canker for a much longer period.
    Copper sprays should begin when the fruit is ¾ inch diameter and continue at 3 week intervals until fully grown in October for best results
  • Copper does not move from where it was applied, so as fruit grows, the new tissue does not have copper to protect it. Disease control on leaves is not possible because of their rapid growth.
  • Homeowners should be aware that these disease management strategies are not completely reliable, but will minimize the disease on trees
  • http://edis.ifas.ufl.edu/pp116 

Citrus Canker Disease on Fruit

Typical citrus canker lesions on fruit will range from 1-10 mm in size. Larger lesions usually penetrate a few millimeters into the rind. Fruit lesions may vary in size and may coalesce. Fruit lesions consist of concentric circles. On some varieties these circles are raised with a rough texture on other varieties the concentric circles are relatively flat like the surface of a record.

The middle of the lesion will be corky in texture with a volcano or pimple like point. The center of a lesion may crack and has a crusty material inside that resembles brown sugar. Frequently on green fruit a yellow halo will be visible; however it will not be visible on ripened fruit.

Lesions may have a water-soaked margin and the water-soaked margin is especially evident on smaller lesions. In the presence of damage the lesion may follow the contours of the damage therefore not being circular. In older lesions a saprophytic white fungus may grow over the center of the lesion.

crater-like lesions

Citrus Canker Disease on Stem

outer layer of bark removed to show brown lesions

Citrus Canker Disease on Leaves

Typical citrus canker lesions on leaves will range from 2-10 mm in size and will have raised concentric circles on the underside of the leaf. Frequently lesions will be surrounded by a water-soaked margin and a yellow halo.

As a canker lesion ages, it may lose it palpable roughness, but the concentric circles will still be visible with a hand lens (on the underside of the leaf). The yellow halo eventually changes to dark brown or black and the water-soaked margin surrounding the lesion may diminish. The middle of the lesion (on underside of leaf) will be corky in texture with a volcano or pimple-like point.

With the exception of very young lesions, lesions always penetrate through both sides of the leaf. In the presence of damage, the lesion may follow the contours of the damage and therefore may not be circular. In older lesions, a saprophytic white fungus may grow over the center of the lesion. The center of a lesion may fall out producing a shot hole appearance.

Yellow halo surrounding leaf lesion


Citrus Phytophthora Fungal Diseases ID with PICTURES

Phytophthora Fungal Diseases
  • Leaf - yellow foliage and shoot die-back
  • Fruit - reduced fruit size and yield
  • Trunk - infected areas results in dark water soaked
    Lesions usually occur on the bark or at the bud union
    Lesions may exude copious amount of gum
    Dead bark tends to break away from the trunk in vertical strips
    Lesions may spread around the circumference of the trunk slowly girdling the tree
  • Whole tree - Poor tree health, thin canopy, failure to make new growth, and little water and nutrient uptake leading to wilting
    Infected root surface becomes soft, discolored and appears water-soaked
  • Most scion cultivars are susceptible to bark infection
  • Most root stocks are moderately tolerant to bark infection
  • http://idtools.org/id/citrus/diseases/factsheet.php?name=Phytophthora

  • Tree dies from starvation
  • Root stock not affected
  • Scion is affected
  • Yellow veins on leaves 
  • Often caused from weed wacker damage
  • Do not plant tree too deep
  • Mongi Zekri Ph.d UF/IFAS 5-County Agent

Phytophthora Fungal Diseases on Trunk

Phytophthora Fungal Diseases on Leaves

Yellow vein symptoms associated with girdling of a young tree by Phytophthora foot rot.

Phytophthora Fungal Diseases on Fruit


Citrus Greasy Spot Disease ID with PICTURES

Citrus Greasy Spot Disease

  • Most severe on grapefruit, lemon, tangelos and early season sweet oranges
  • Grapefruit is highly susceptible
  • Found on fruit and leaves 
  • First appear as yellow spots on the upper leaf surface, with a corresponding slightly raised, pale orange to yellowish brown blister on the lower surface
  • Later the symptoms on both surfaces become darker brown or black and show a more 'greasy' appearance
  • Fruit - fruit exhibit necrotic specks in the epidermis between the oil glands
  • http://idtools.org/id/citrus/diseases/factsheet.php?name=Greasy+spot

  • Two sprays are needed to control greasy spot in southwest Florida. The first spray should be scheduled in May-June and the second in July-August. Thorough coverage of the underside of leaves with Copper Fungicide plus Oil is important and necessary for the control of greasy spot
  • http://edis.ifas.ufl.edu/hs141
  • Splashed appearance on BOTH SIDES
  • Mongi Zekri Ph.d UF/IFAS 5-County Agent

Citrus Greasy Spot Disease on Fruit

Greasy spot rind blotch on grapefruit.

Close-up of rind blotch on grapefruit.

Individual rind blotch lesions between oil glands on grapefruit.

Citrus Greasy Spot on Leaves

Greasy spot symptoms on grapefruit leaves.

Greasy spot symptoms on the upper and lower leaf surfaces.