james gerik* ,sadikshya dangi , and husein ajwa … mbao...treatments the plots were approximately...

James Gerik*1,Sadikshya Dangi1,2, and Husein Ajwa2

1USDA-ARS; 2University of California-Davis; 3

Calla Lily Approximately 300 acres of Calla are planted in the

spring each year.

The crop cycle last approximately 18 months and the crop goes dormant during the winter.

Bulbs (rhizomes) are harvested at the end of the crop cycle and flowers may be cut during the second summer.

All acreage is fumigated before planting (QPS exemption).

Objectives Past experiments have shown that calla lily can be

successfully grown using alternative fumigants. These have included combinations of chloropicrin (Pic), 1, 3-dichloropropene (1, 3-D), and potassium metam (K-Pam). An experiment is being conducted to determine the lowest effective rates that these chemicals can be successfully used to grow this crop.

Treatments The plots were approximately 500 feet long and

consisted of raised beds 72 inches wide.

The main plots were fumigated with either InLine (1, 3-D 60.8%, Pic 33.3%) or Pic-Clor 60 EC (Pic 56.7 %, 1, 3-D 37.1%) or left untreated.

Both fumigants were applied at three rates: 20, 17, and 14 gallons per acre.

Treatments One week after the initial fumigation the sub-plots

were fumigated with one of four rates of K-Pam: 0, 28 34, or 40 gallons per acre.

All fumigants were applied through five drip irrigation tapes on the surface of the beds beneath virtually impermeable film.

0

500

1000

1500

2000

2500

3000

3500

4000

control IL-14 IL-17 IL-20 PC-14 PC-17 PC-20

Fumigation Treatment

Fusarium oxysporum CFU/g

0

28

34

40

K-

0

200

400

600

800

1000

1200

control IL-14 IL-17 IL-20 PC-14 PC-17 PC-20

Fumigation Treatment

Pythium spp. CFU/g

0

28

34

40

K-Pam

0

20

40

60

80

100

120

140

control IL-14 IL-17 IL-20 PC-14 PC-17 PC-20

Nu

mb

er

/ I

m b

ed

le

ng

th

Fumigation Treatment

Stand Count

0

28

34

40

K-Pam

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

control IL-14 IL-17 IL-20 PC-14 PC-17 PC-20

Dis

ea

se R

ati

ng

(0

-5)

Fumigation Treatment

Disease Rating 7/21/2012

0

28

34

40

K-Pam

Control

InLine 14

InLine 17

InLine 20

PicClor 14

PicClor 17

PicClor 20

Conclusions The populations of F. oxysporum were not significantly

reduced at any rates of the primary fumigants.

The fumigants did a much better job in reducing populations of Pythium spp. compared to F. oxysporum; we have observed this before in past experiments when using these fumigants.

Conclusions The stand of calla lily was not affected by the soil

treatments.

Disease control was better with InLine compared to Pic-Clor.

Disease control improved with the higher K-Pam treatments

The trial will continue until the end of 2012 when the bulbs will be harvested and disease incidence and yield results collected.

Thanks to the Pacific Area-Wide Methyl Bromide Alternative Program for Funding for the Last Five Years.