Evaluation of Insect Repellents and Barriers as Methods to Control Cucumber Mosaic Virus of Bell

Peppers

Joe NunezVegetable/Plant Pathology Advisor

UC Cooperative Extension-Kern

Cucumber Mosaic Virus

• CMV has been afflicting peppers in Kern County for 5 years.

• Appears most heavily in the southern end of the county near Mettler.

• Some years worst than others. • The earlier it appears in the season,

the more damage occurs. • Is aphid transmitted.

Control of CMV• Essentially none-remove weeds around

field and reflective mulches

• Plants are treated with imidacloprid as seedlings in greenhouses.

• Imidacloprid treatments continue through season.

• Organic fields treated with biologicals.– Lady bug release– Lacewing, etc

Control of CMV

●Even with insecticide treatments, aphids will probe and transmit the virus before it is killed.

•Must prevent aphids from landing on plants.

2010 Trial

1. Control

2. Black

3. Silver reflective

4. Silver

5. White

6. Green

7. Red

8. Surround Canopy

9. Surround Soil

White Control Silver Reflective

Silver Green Red

Surround on Soil Surface

Surround on Canopy

Surround Canopy Surround Soil

Green Mulch

Red Mulch

Black Mulch

White Mulch

Fresh Wt (g) ___ 5/21/10 Treatment Top Wt. Root Wt. Total 1. Control 533.0 cde 53.0 ab 586.0 cd 2. Black 631.0 abc 55.5 a 686.5 abc 3. Silver Reflective 467.0 e 44.5 c 511.5 d 4. Silver 669.5 ab 58.0 a 727.5 ab 5. White 582.0 bcd 53.0 ab 635.0 bc 6. Green 697.5 a 60.0 a 757.5 a 7. Red 662.0 ab 60.0 a 722.0 ab 8. Surround Canopy 460.5 e 45.5 bc 506.0 d 9. Surround Soil 520.5 de 55.5 a 576.0 cd

P= 0.0003 0.0015 0.0003 %CV= 12.64 9.72 12.10 LSDp=0.05 107.1 7.645 112.0

0

100

200

300

400

500

600

700

800

gra

ms

1. Control 2. Black 3. Silverreflective

4. Silver 5. White 6. Green 7. Red 8. SurroundCanopy

9. SurroundSoil

Total Fresh Weight

cdabc

d

abbc

a ab

dcd

Dry Wt (g) ___ 5/21/10 Treatment Top Wt. Root Wt. Total 1. Control 55.4 bcd 6.9 c 62.3 cd 2. Black 64.1 ab 7.9 abc 72.0 ab 3. Silver Reflective 49.4 d 6.8 c 56.1 d 4. Silver 68.5 a 8.6 ab 77.1 a 5. White 58.9 bc 7.1 bc 66.0 bc 6. Green 71.3 a 8.8 a 80.0 a 7. Red 68.9 a 7.3 abc 76.1 a 8. Surround Canopy 47.8 d 8.0 abc 55.8 d 9. Surround Soil 54.9 cd 6.9 c 61.8 cd

P= 0.0000 0.0707 0.0000 %CV= 10.48 13.85 9.03 LSDp=0.05 9.163 1.530 8.891

0

10

20

30

40

50

60

70

80

gra

ms

1. Control 2. Black 3. Silverreflective

4. Silver 5. White 6. Green 7. Red 8. SurroundCanopy

9. SurroundSoil

Total Dry Weight

Series3

cdab

d

abc

a a

dcd

Yellow Sticky Cards – placed above canopyWeekly aphid and thrips counts

Aphid Trap Counts

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

Num

ber o

f Aph

ids

1. Control

2. Black

3. Silver reflective

4. Silver

5. White

6. Green

7. Red

8. Surround Canopy

9. Surround Soil

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

Nu

mb

er o

f A

ph

ids

1. Control 2. Black 3. Silverreflective

4. Silver 5. White 6. Green 7. Red 8. SurroundCanopy

9. SurroundSoil

Total Aphids for Season

a

bcdd d

bccd cd

b

cd

Thrip Counts

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

3500.0

4000.0

Num

ber

Thri

ps

1. Control

2. Black

3. Silver reflective

4. Silver

5. White

6. Green

7. Red

8. Surround Canopy

9. Surround Soil

0.0

1000.0

2000.0

3000.0

4000.0

5000.0

6000.0

7000.0

8000.0

9000.0

10000.0

Nu

mb

er o

f T

hri

ps

1. Control 2. Black 3. Silverreflective

4. Silver 5. White 6. Green 7. Red 8. SurroundCanopy

9. SurroundSoil

Total Thrips for Season

bbcde cde de

a

bcd bcdee

bc

Totals Treatment Market Process Total 1. Control 6.7 abc 3.4 10.1 2. Black 7.4 ab 3.4 10.7 3. Silver Reflective 5.5 c 3.5 9.0 4. Silver 8.4 a 3.6 12.0 5. White 6.5 bc 3.2 9.7 6. Green 7.5 ab 2.9 10.4 7. Red 7.3 ab 3.8 11.1 8. Surround Canopy 5.6 c 3.6 9.2 9. Surround Soil 6.9 abc 3.4 10.3

P= 0.0425 0.9167 0.2145 %CV= 17.31 24.09 15.06 LSDp=0.05 1.737 NS NS

Harvest Data

0

2

4

6

8

10

12

14

Kg

1. Control 2. Black 3. Silverreflective

4. Silver 5. White 6. Green 7. Red 8. SurroundCanopy

9. SurroundSoil

Harvested Weights of 12 plants

Processing

Marketableabc abc

a

bc ab abc abc

Conclusions from 2010 Trial

• All mulches, plastic or kaolin clay, can reduce aphid flights into peppers.

• Silver reflective, Silver & Kaolin clay on canopy reduce thrips populations in plant canopy.

• Silver, Green & Red mulches increase plant growth of peppers.

• CMV was not a problem in 2010

Summary for the 3 year study

• Reducing aphid flights into pepper fields reduces the incidence of CMV.

• Reducing incidence of CMV increases yields.

• Plastic mulches, especially silver reflective, are very effective at reducing aphid and thrips populations in a field.

• Red and Green plastic mulch increase plant size and pepper yields.

Summary for the 3 year study

• Kaolin clay as a mulch may be less expensive, easier, and more environmentally sound method to reducing aphid populations.

• Botanical oils sold as insect repellents are not effective.

Thanks to:

Valprado FarmsMike ValpredoRick MartinezOmar Martinez

California Pepper Commission