Curly Top Virus Research in Tomatoes 2009

The 2009 Curly Top Virus research was a simple replicated comparison of reflective and red plastic mulch in tomatoes. It was conducted at the Western Colorado Research Center at Orchard Mesa.

Mulch Color Trial

Tomato PlantsFour varieties of curly top virus susceptible tomatoes were used in the trial. All were paste types purchased from Totally Tomatoes. They were 'Opalka', 'Sausage', 'TT Roma', and 'Viva Italia'. Seeds were planted and grown for approximately 6 weeks in the greenhouse before planting.

Each variety was used as a replication with about 62 plants planted each on reflective and red plastic mulch. Mulch color was randomly assigned to each row half.

The trial was conducted in old tree rows of an orchard that had been removed. The area between the plant rows was left in established alfalfa, which was occasionally mowed during the season.

Plastic mulch and drip tape was laid with a mechanized mulch layer. Click on the picture for a video of the mulch laying process.



Planting Tomatoes

Tomato seedlings were transplanted May 4th. They were planted at 34" spacing. We utilized volunteer labor to assist with the planting.

3" x 5" yellow sticky cards were used to monitor insect movement within plots. They were placed at plant height near the middle of each plot and changed weekly. Card height was increased as plants grew. The cards were taken to the lab where thrips, aphids, and leafhoppers were counted. No attempt was made to identify the insects beyond family level.

Planting TomatoesYellow Sticky Trap

Evaluation and Results

GraphThe line graph below shows capture trends through the season. Thrips captures increased throughout the season while there was little change in the leafhopper and aphid captures. By early July the tomato plants had completely covered the mulch and it was no longer visible.

Total thrips and leafhopper captures were greater on red than on reflective mulch (p>0.01). Differences in aphid captures were not statistically significant(p<0.05).The bar graphs at the left show insect capture data throughout the growing season.

Beet Curly Top (BCT) infection was visually evaluated each time the yellow sticky traps were changed. The first BCT symptoms were noted in the week ending 29 June. No curly top infected plants were found in tomatoes grown on reflective mulch. One BCT infected plant was found in each of the varieties (replications) grown on red mulch. A second curly top infected plant was found in Viva Italia on 13 July.

Reflective mulch was effective at reducing BCT infection rate in this low disease pressure year as shown by the bar graph to the lower right. Leafhopper captures were very low throughout the growing season, which resulted in the low overall disease pressure.


Harvesting Tomatoes

More than a ton of tomatoes were harvested from the field and utilized by a local salsa production farm. In addition more than 300 lbs. of late season tomatoes were donated to local food banks.

'Opalka', while producing large, flavorful tomatoes, yielded few fruit with short shelf life. 'Sausage' produced a moderate yield of fruit, but we were disappointed in the size. 'Viva Italia' and 'TT Roma' had high yield of high quality fruit. In a separate variety evaluation, 'Incas', 'Martino's Roma' and' Tormenta' produced large, flavorful, firm fruit with good shelf life.

Harvesting TomatoesTomatoesTomatoes

This page was updated on April 26, 2014