Note: Please bring laptop computers for Laboratory 19

Purpose:   Economics of the nematode management decision process:  integration of information on plant host-status, nematode biology, and economics of nematode management.

1.  Powerpoint presentation and slides:  Host plant resistance and chemical management.

2.  Complete soil suppressiveness test from Lab. 17 and report data

3.  Use of Nemabase, Nemaplex Threshold Calculators, Host Status of Crops, Crop Sequence Optimizer, Crop Sequence Selector.
a.  You are a pest management consultant hired by a farming operation in the southern San Joaquin Valley.  They have purchased 640 acres of land on which they would like to grow cotton (Gossypium hirsutum).  The following circumstances exist:

        i.   the soil texture is sandy loam
        ii.  the soil moisture is currently 8%
        iii. the date is March 1, 2011
        iv.  the soil temperature is 12 C
        v.   the proposed planting date is April 15, 2011
        vi.  the field is fairly uniform and has the following average nematode densities:

        vii. the company is willing to consider rotation to other annual crops, or the use of resistant cultivars (if available).
Note:  assume that while available resistant cultivars yield well in the presence of the target nematodes, they have certain quality attributes that reduce their market value by 10%.

b.  The company requests that you examine the various rotation and host plant resistance alternatives. Summarize expected costs and returns of  each approach.

c.  They have an alternative: to trade the land for a similar acreage in the coastal region.  The area has 400 M. javanica per kg soil, and the soil is a clay loam with current moisture content of 15% and temperature of 10 ºC.  However, that area is not suitable for cotton production.

Hints: 

1.     Use Nemabase to determine host status of crops to the nematode species present.
2.     Use Nemabase to determine availability of resistant cultivars.
3.     Use the Nemaplex Crop Sequence Selector for recommendations of plants to include in a rotation for this group of nematodes.
4.     Use the Economic Threshold Calculator in Nemaplex to determine the economic threshold for a resistant cultivar (the cost of the cultivar is the reduction in net value in the absence of nematodes).
5.     Use the Optimum Non-host Rotation Model (Cropping Sequence Optimizer) to determine length of nonhost rotation and weighted annual returns.

6.    Access the Economic Threshold Calculators and Crop Selectors in Nemaplex by:
                    Main Menu
                       Decision Support
                             Economic Threshold Calculator

                                    Crop Sequence Selector

                           Cropping Sequence Optimizer

                      

                            Host Status of Crops

 Consider M. incognita the key pest in the system.  But...how will you deal with the other species?

        Are your recommendations the same for the alternate area, and would the trade result in greater profit?   By reporting in class, explain to the company any estimates that you have had to make, and your basis for making those estimates.

Sample crop prices and production costs.

Annual survival rates (s) under non-host crops for the nematode species are:     

Damage function parameters and annual nematode multiplication rates for Meloidogyne incognita on cotton and a non-host crop are:          

References:

Ferris et al. 1986.  California Agriculture.
Burt and Ferris. 1996.  Journal of  Nematology.

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