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Artichoke

                                                               Artichoke Diseases


1- fungal diseases :


1-1- Damping-off

The causal organisms:
There are many pathogens can cause  damping-off  such as
                   Fusarium solani             Rhizotonia solani           Phthium spp,
 Symptoms :
Damping off can occur before or after crop emergence . Pre-emergence damping-off results
in a brown, gelatinous rotting within the seed coat.  Radicles and cotyledons may become brown and soft after germination, but fail to emerge.  Water-soaked, greasy lesions may also form on hypocotyls and roots after emergence when infected with Pythium spp., causing plants to collapse and wither. Post – emergence damping-off caused by R.solani begins as elliptically-shaped, brown to black sunken cankers on roots and hypocotyls, with a sharp margin between infected and healthy tissue.  Plants can become girdled and die, but lightly infected roots often survive and produce nearly normal roots. 
Control:
If the causal organism is Rhizoctonia solani
We can use
MONCUT 3G/1Kg seeds
Or     MONCUT 500g/400L.W (with irrigation)


1-2- Verticillium wilt:
The main fungi is Verticillium dahlia, but sometime Fusarium oxysporum  can cause wilt
Symptoms:
- Verticillium dahlia is a soil borne fungus that invades the plant through the root, and grows into the vascular system causing a reduction in water flow through the plant.
- The leaves of infested plants turn to yellow color and wilted plants usually die
- The pathogen is able to survive in the soil for long periods of time as structures called microsclortias .The microsclortia are produced in plant tissue, and can survive and be spread in plant debris
- substances produced in the plant during infection may also result in discoloration of the vascular tissue. Brown streaks or flecks often can be observed in cut stems and are diagnostic of the disease
Control:
There is no control for verticillium wilt and to date resistant cultivars are not available, Avoidance of known infested fields and rotations of several years are recommended.

1-3- Root Rot

The causal organisms:
There are many pathogens can cause  damping-off  such as
 - Phytophthora spp.
- Rhizotonia solani
- Fusarium solani

Symptoms:
- All the above pathogens are soil borne fungi penetrate the host through the root system causing a reduction in water and nutrition follow through the plant.
- Infested plants wilt and its leaves turn to brown color and the root system completely turn to black
Control :
If the causal organism  is Rhizoctonia solani
we can use           
MONCUT 3G/1Kg seeds
Or     MONCUT 500g/400L.W


1-4 Powdery mildew

The causal organisms:    Leveillula taurica
Symptoms:
- The causal organism is more commonly found and primarily colonizes the undersides of older leaves and yellow spots on the upper services.
- Careful examination of leaf undersides reveals spores produced singly or in very short chains; however, the profuse white hairs of the leaf may obscure this sign
- Severely infected leaves will turn yellow, then brown
- By the time , the brown leaves may collapse and dry up
- The pathogen infects only the older leaves; the younger leaves escape infection until they mature

Control:
Use one of the following

Before Symptoms appearance:         Kumulus –S         300g/100L.W
After  Symptoms appearance:  TILT                    15 cm /100L.W
OR    Amistar                 300cm/fadden
OR    Amistar Top        200cm/fadden
OR    Bellis                    50g/100L.W
OR    Cabrio top                      100g/100L.W


1-5 Gray Mold
The causal organisms:    Botrytis Cinerea
Symptoms:
- The pathogen is capable of colonizing on artichoke leaves and damage it
- the main concern with this fungus is when it gets on the flower bracts
- This fungus usually invades bracts that have been damaged from insects, frost, or other factors
- Infected bracts turn brown on the outside .On the inner surface of the bracts the characteristic gray growth of Botytis  develops.
Control :    Use     Bellis                    50g/100L.W

2-Viral diseases:
The most common viral diseases on artichoke cultivation are:
a- Mosaic virus                                 b- Stunting and curl virus
c- Curling virus                                 d- Latent virus

- Transmission of viruses:
- The causal organisms can transmit by may Ways
A: Michanicaly:
- Tools  of  agriculture
- Contact between workers and infested plants
- Contact between Infested plants and healthy one.
B: By Insects:
- Aphids - white fly

Symptoms:
- Infested Plants show significant reduction of growth and vigor and become severely stunted
-Leaves are distorted and can have dark, necrotic spots and sections
- Infected plants are less proactive, having up to 40 % less yield than healthy plants

3-Insects of Artichoke:


A: In nursery:

1-A- white fly:
  Bemisia tabaci

Description of the pest
Silver leaf whitefly adults are tiny ( 0.06 inch, 1.5 mm long), yellowish insects with white wings. Their wings are held somewhat vertically tilted, or roof like, over the body and generally do not meet over the back but have a small space separating them.

Whiteflies are found mostly on the undersides of leaves. They fly readily when plants are disturbed. The tiny, oval eggs hatch into a first nymph stage that has legs and antennae and is mobile. The legs and antennae are lost after the first molt and subsequent stages remain fixed to the leaf surface. The last nymphal stage, often called the pupa or the red-eye nymph, is the stage that is easiest to identify. Silver leaf whitefly pupae are oval and soft. The edge of the pupae tapers down to the leaf surface and has few to no long waxy filaments around the edge
Damage
Damage by silver leaf whitefly is mostly a problem in annual plantings of artichoke in warm climates. Feeding by whiteflies produces sticky honeydew on the leaves. Sooty mold may grow on the excreted honeydew. Artichoke seedlings and transplants may be stunted by silver leaf whitefly feeding

Control:
Use on of the following

Perfekthion 40%            400cm/Fadden
Or     Actellic       50%            375cm/100L.W
Or     Applaud     25%            100cm /100L.W
Or     Mospilan    20%            25g/100Fadden
Or     Nudrin        90%            300g/Fadden
Or     NOMOLT   15%            50cm/100L.W


A: Leaf miner:

Liriomyza Trifolii

Description of the pest
Adults are small black to gray flies with yellow markings. Females puncture leaves to feed on plant sap and lay eggs within the leaf tissues. After 2 to 4 days eggs hatch and larvae feed between the upper and lower surface of the leaves, making distinctive winding, whitish tunnels or mines that are often the first clue that leaf miners are present. Larvae emerge from the mines and pupate on the leaf surface or, more commonly, in cracks in the soil. Many generations occur each year and the entire life cycle can be completed in less than 3 weeks when the weather is warm.

Damage
The primary damage caused by the leaf miner is the mining of the leaf by the larvae. When infestations are severe, the plant's photosynthetic capacity is reduced and there is a reduction in crop yield.

Control:
Use on of the following

Perfekthion 40%            400cm/Fadden
Or     Mospilan    20%            25g/100Fadden
Or     Pleo            50%            100cm/Fadden
Or     NOMOLT   15%            50cm/100L.W


Description of the pests
Several species of aphids may be found on artichoke plants. These aphid species vary in color (from light green to black), size, and shape. All are soft-bodied insects. The most important aphid pest is the artichoke aphid, which is covered separately. Other aphids that may occur include green peach aphid, black bean aphid, and pea aphid. They form dense colonies on the undersides of artichoke leaflets and in some cases on the artichoke petioles. Winged aphids form under specific conditions of overcrowding or plant stress and disperse to other plants or fields.

The green peach aphid occurs sporadically throughout the year. Populations start on lower leaves. In heavy infestations, they may be found throughout the plant. On the central coast, populations peak in spring and fall and decline in summer and winter. Spring populations generally build up on weed hosts occurring in the field and in uncultivated areas around the fields and move to artichokes during March and April. In the southern coastal areas, populations generally peak in September to November and again in March to April. In the southern desert area where artichokes are planted as an annual crop in August, green peach aphids attain peak densities in January and February when the crop is ready for harvest.

Occasionally pea aphid and black bean aphid infest artichokes that are located close to other row crops.

Damage

Unlike artichoke aphid, green peach aphid does not lower yields or turn leaves yellow. Damage is more cosmetic in nature when green peach aphid move into artichoke buds, contaminating the outer bracts. At low to moderate infestation levels, these aphids can be removed by washing the produce with water before packing. However, as the growers move towards field packing, these low infestations may become more economically significant.


Occasionally black bean aphid populations move into developing floral heads, which can require the heads to be culled. Also, the aphids produce honeydew, upon which black sooty mold grows and contaminates the artichokes.

Control:
Use on of the following
Perfekthion 40%          400cm/Fadden
Or     Actellic       50%           375cm/100L.W
Or     Aphox        50%           50cm /100L.W
Or     Mospilan    20%           25g/100Fadden
Or     Nudrin       90%           300g/Fadden

B: Open field:
1- B- Cotton leaf worm:

 Spodoptera Littoralis
Description
- Adult: the moth has a wingspan of 35 to 40 mm. Fore wings are brownish with bluish overtones and straw yellow along the median vein; the callus is marked by 2 or 3 oblique whitish stripes. The front of the wing tip has a blackish marking, more pronounced in the male. Hind wings are whitish, with a brown front edge.
- Egg: about 0.6 mm long, more or less spherical. Eggs are laid in clusters and covered with brownish-yellow hairs detached from the abdomen of the female.
- Larva: the neonate caterpillar is pale green with a brownish head; when fully developed it is 35 to 45 mm long.
Color varies: from grey to reddish or yellowish, with a median dorsal line bordered on either side by two yellowish-red or grayish stripes, and small yellow dots on each segment.
The edges, more or less dark grey, bear triangular markings which on the 1st and 8th segments become 2+2 large, triangular, velvety black markings. The underside of the caterpillar is grayish-red or yellowish.

Life Cycle
- In its region of origin (Egypt), some ten generations occur each year; in greenhouses, only 7 are possible, depending on the conditions, which may cause its migration.
- This moth overwinters as a pupa in the soil.

Damage
In Italy, mostly found in glasshouses where it causes damage to plant and flower production, recognizable by the large bites taken out of leaves.
In Sicily, vegetables and fodder crops are affected, as well as maize.
In Egypt, it is one of the most serious cotton pests

Control:
Use on of the following

Pleo            50%           100cm/Fadden
Or     NOMOLT  15%           50cm/100L.W
Or     Challenger           36%           45cm/100L.W

Address: Km 28, Cairo - Alex Desert road, Starchem building.
Phone:202-35391811/2/3 202-35391515 Fax: 202-35391814