Progress report for LNE16-353

Methods to test hypothesis 1:

This hypothesis will be tested by implementing one year of field trials in two locations: Western New York and Eastern New York. Sites will be chosen in part for variation in soil type, and we also expect based on historical weather data to see different growing conditions in each site. The trials will be hosted on farms which have a history of struggling with field diseases. In each case the trial will be planted with seed which has tested positive for fusarium, and baseline infection rates of fusarium and botrytis prior to planting will be rated.

Treatments (all planted in German White unless noted, fall planted unless noted, and all with optimum fertility):

• Raised bed, white plastic
• Raised bed, black plastic
• Raised bed, straw mulch
• Raised bed, bare ground
• Raised bed, spring planted bare ground
• Raised bed, spring planted straw mulch
• Flat ground, white plastic
• Flat ground, black plastic
• Flat ground, straw mulch
• Flat ground, bare
• Flat ground, bare, spring planted
• Flat ground, straw mulch, spring planted

This trial will be set up in blocks by raised bed and flat ground, with randomization within these treatments. Each treatment will have four replications.

Data collection:

6 leaf stage: A stand count, plant uniformity, and disease/damage rating will be performed on each plot. Suspicious samples will be sent to Geneva for testing.

6-7 leaf state: Plant uniformity and disease/damage rating, with suspicious samples sent to Geneva.

Early bulbing: Plant uniformity and disease rating, with suspicious samples sent to Geneva.

Harvest/after drying: Final stand count, disease rating, and final yield/average bulb weight will be measured. A subsample of each treatment will be withheld for disease incubation.

Methods to test hypothesis 2:

This hypothesis will be tested by implementing field trials in two locations: Western NY and Long Island. Because the trials are being inoculated with fusarium, they will be hosted at research farms.

 Treatments:

• Clean seed, optimum nitrogen
• Inoculated clean seed, optimum nitrogen
• Naturally infested seed, optimum nitrogen
• Clean seed in inoculated ground, optimum nitrogen
• Clean seed, low nitrogen – 50 lb/A
• Clean seed, High nitrogen – 150 lb/A 
• Clean seed, optimum nitrogen, Oxidate dip + Terraclean drench every 14 days
• Inoculated clean seed, optimum nitrogen, Oxidate dip + Terraclean drench every 14 days
• Naturally infested seed, optimum nitrogen, Oxidate dip + Terraclean drench every 14 days
• Clean seed in artificially inoculated ground, opti nitrogen, Oxidate dip + Terraclean drench every 14 days
• Naturally infested seed in low nitrogen
• Naturally infested seed in optimum nitrogen
• Naturally infested seed in high nitrogen

Data collection: same as for hypothesis one, with the addition of foliar nitrogen sampling at 6-7 leaf stage in fertility treatments.

Farmer input: Growers have long grappled with the question of where fusarium comes from—is it in the seed or the soil? Is all fusarium the same? Growers (and vegetable specialist) also express concern about hydrogen dioxide dips not effectively controlling disease. Finally, growers have expressed concern that garlic, like many other crops, becomes “too soft” with excess fertility and becomes more susceptible to disease.

Field observational study:

Hypothesis: Garlic is suffering from different species or subspecies of Fusarium which vary in severity and primary inoculum source, and vary by garlic variety.

Broad sampling of industry in Northeast to determine variation in Fusaria:

August 2016: Examine samples collected throughout harvest 2016 season which exhibit fusarium symptoms (up to 90 samples from the Northeast)

July 2017: Repeat sampling at harvest in Northeast to determine if Fusarium species/type varies from year to year (additional 90 samples)

Intensive sampling for progression: 8 farms will be sampled in two varieties each: Porcelain and Rocambole (or other non-porcelain variety). Sampling will occur 4 times at distinct growth stages:

• Garlic at 6 inches
• At 6-7 leaf stage
• At early bulbing
• At harvest (if needed)

5 plants of each variety which appear unhealthy will be harvested and sent to Geneva for evaluation at each sampling.

Trial-maps-2016-2017

Plot-Plans-Garlic-2018