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New book by  V. I. Koshnikovich A. G. Shcherbinin N. N. Timoshenko

Cucumber Downy Mildew

The cucumber downy mildew

 

In the edition we there is the information about the species composition of the cucumber diseases and the similarities of the diseases composition in different regions. There is also an estimation of the cucumber biological capabilities from the phytopathological point of view.

The main consideration is given to the downy mildew causative agent. The questions about the pathogen biology, the spreading and the morphological and structural peculiarities are examined, and the mechanism of injuriousness is worked out by means of the mathematical analysis. According to the biological data and the data of the intraspecific variety, the questions of epiphytotiology are described here.

The edition gives the information about the long-term forecasting of the downy mildew in Siberia and the analytic models on the basis of the indexed combining of the prognostic factors. The authors have worked out the methodology of the indexed estimation of the varietal collections. The possibilities of the agrotechnical, biological and chemical control of the downy mildew epiphytoties. 

The edition is oriented for students, scientists and manufacturers.

It is recommended for publication by the scientific council of the agronomic department of the Novosibirsk state university of agriculture.

Some moments from the book:

 

The extrahaustorial matrix (fragment), zoom 118000

(by A. G. Shcherbinin and U. M. Plotnikova, 1992)

 

-         H – haustorium

-         C – capsule of haustorium

-         E – electron-consistent zone

-         Cl – clear zone for electrons

-         Ex – extrahaustorial membrane

-         L – lipids

-         M – mitochondria

-         En – endoplasmic reticulum

 

The types of the P. cubensis zoosporangia germination:

 

-         Saprolegnoid (on the left)

-         Pithioid (on the right)

 

The cultural host-plants of the P. cubensis fungus

(Siberian research institute of plant growing and selection, 1989-1991)

Species

Sort, of the virus catalogue

Reaction on P. cubensis

1989

1990

1991

1. Cucumis sativus L.

Vyaznikovsky 37

+++*

+++

+++

2. C. melo L.

Kolhoznitsa

n

+

++

3. Cucurbita pepo L.

Mozoleevskaya

-

+

+

4. C. pepo var. giraumontia Duch.

Gribovskiye

(*)

-

(*)

5. C. pepo var. patisson Duch.

Beliye 13

-

-

(*)

6. C. pepo ()

K 4566, USA

Gk 0,39, USA

-

n

(*)

n

n

(+)

7. C. maxima Duch.

Volzhskaya series

+++

++

+++

8. C. moschata Duch.

Muskatnaya

K 4506, Pakistan

n

n

n

n

+

+

9. Cittullus vulgaris Schrad

Ogonek

n

(*)

+

*+++ High degree of affection, spores

++ Medium degree of affection, no spores

+ Low degree of affection

(*)Ultrasensitive reaction

-  – No symptoms

n – Tests have not been carried out

 
The equation of regression of the degree of the cucumber leaf area affection by downy mildew, according to the decade air temperature in June, is the following:
 
´3 = 6,1941-5,70722+227,649x2-0,811 32+37,6803-2740,750              
1  - the medium air temperature in the 1st decade of June,
X2 - the medium air temperature in the 2nd decade of June,
X3 - the medium air temperature in the 3d decade of June.
 
The medium quadratic divergence of the empiric data from the theoretical ones of the equation is 6,1 %. The model can be used on conditions that the changing of the medium air temperature between: 13...21 in the 1st decade, 18...23 C in the 2nd decade and 15...22 C in the 3d decade of June.