In-Season Control of Pepper Diseases and Insect Pests
» Diseases and insect pests of pepper may require the use of in-season control measures.
» Cultural practices and chemical treatments can help manage disease and insect problems during the season.
» Regular field scouting is needed for adequate management of some diseases and insect pests.
This article will use example disease and insect pests to
describe management practices that can be implemented
during the season to protect yield and fruit quality. This
article will not cover management strategies that would be
initiated at or before planting such as crop rotation or use of
host resistant varieties.
Anthracnose can affect all above-ground parts of the plant.
Infections of the fruit are the most economically important,
and fruit become more susceptible to infection as they
mature and ripen.1
The fungi that cause anthracnose on peppers can infect a
large number of hosts. Therefore, managing weed species
that can serve as sources of the disease is important.2
Because the spores of the fungus are disseminated by
splashing water, avoiding overhead irrigation can help slow
the spread of the disease. Managing insects that wound the
fruit can also reduce the chances of infection.
The application of foliar fungicides (Table 1) can provide
some control of the disease if inoculum levels in the field are
low or when conditions are not optimal for infection and
disease development. Copper-based fungicides provide
limited protection from anthracnose, but they can be used
in certain circumstances in organic production systems.1
Fungicide applications should begin when the first fruit
begin to mature and continue to be applied as directed by
the label instructions, usually on a seven to ten day interval.3
Southern blight (also called basal stem rot) is a destructive
disease that occurs in warm, humid regions of the U. S.
where daily winter temperatures rarely drop below freezing.
The fungal pathogen has a wide host range of over 500 plant
species. On peppers, the pathogen causes damping-off of
seedlings and stem rots of older plants.1
In-season management options for southern blight include
rouging-out (removing) infected plants (when this is
economically feasible), controlling weeds that can serve as
hosts for the pathogen, and avoiding injuries to the plants
during cultivation that can increase the rates of infection.
Because the disease is favored by low soil pH levels, in-
season fertilization with ammonia based fertilizers can result
in lower rates of southern blight than are seen when nitrate
fertilizers are used.1
In fields that have been strip-fumigated, avoid overhead
irrigation that can splash pathogen-infested soil from
between the beds onto the plants. The application of
fungicides can provide some control or suppression of
southern blight (Table 1), and several biological control
agents, including species of Trichoderma, Gleocladium virens,
and Bacillus subtilis are commercially available to help
reduce the damage caused by southern blight.1
Several species of thrips can occur on peppers, but not all
species cause problems. In fact, native species of thrips can
out compete pest species and prevent damage. The western
flower thrips (WFT) is the species that causes the most
problems on peppers grown in the U.S. The primary damage
associated with WFT feeding results from the transmission
of the Tomato spotted wilt virus (TSWV), as WFT is the major
thrips vector for this virus.5,6 Feeding of large populations of
WFT can cause direct damage including distortions and
silvering of leaves and fruit.
The population levels of various thrips species can be
monitored using yellow sticky traps and through scouting
and inspection of plants. When scouting, collect ten flowers
from each of several randomly selected location in the field,
and examine small, medium, and large sized fruit by looking
for insects under the calyx. Count the number of larvae per
fruit. Six WFT per flower or two per fruit is tolerable, counts
above that may indicate the need for treatment. Do not treat
for eastern flower thrips or other non-pest species.5
When treating for thrips, the primary goal is to prevent
damage, not to kill the insects. Using reduced risk
insecticides, such as spinosad and spinetoram, in
combination with natural and released predators can
provide effective control.5 If multiple applications are
required, rotating classes of insecticides (Table 2) can help
prevent or delay the development of insecticide resistance
in thrips populations. Some of the insecticides used to
manage thrips are harmful to bees and other pollinators.
Special precautions may be needed to protect these
beneficial insects from exposure.6 Always consult the most
up-to-date product label for directions and restrictions.
Some products may not be registered for use in all states.
Adult pepper weevil feed on fruit and leaf buds causing
damage, while weevil larvae feed inside of the pods. Larval
feeding can cause young fruit to drop prematurely, and the
presence of larvae reduces the marketability of larger fruit.
Management efforts should include removing culled and
dropped fruit from the field to reduce sources of infestation.
To determine if treatments are needed, use pheromone
baited sticky traps or examine terminal buds to monitor
weevil populations. Check traps or scout twice a week, and
treat when the first adult is detected.7 Insecticides can be
used to treat weevil infested fields (Table 3), but measures
should be taken to protect bees and other beneficial insects.
1 Pernezny, K., Roberts, P., Murphy, J., and Goldberg, N. 2003. Compendium of pepper diseases. American Phytopathological Society.
2 Koike, S., Davis, R., and Subbarao, K. 2016. Peppers: Powdery mildew. UC IPM, UC Pest Management Guidelines. UC ANR Publication 3460.
3 Reiners, S., Bellinder, R., Curtis, P., Helms, M., Landers, A., McGrath, M., Nault, B., and Seaman, A. 2017. Cornell integrated crop and pest management guidelines for commercial vegetable production.
4 Vegetable Production Handbook of Florida 2015-2016. UF-IFSA
5 Funderburk, J., Reitz, S., Stansly, P., Freeman, J., Miller, C., McAvoy, G., Whidden, A., Demirozer, O., Nuessly, G., and Leppla, N. 2015. Managing thrips in pepper and eggplant. University of Florida IFAS, ENY-658.
6 Natwick, E., Trumble, J., and Aguiar, J. 2016. Thrips. UC Pest Management Guidelines: Peppers, UC ANR Publication 3460.
7 Natwick, E., Trumble, J., and Aguiar, J. 2016. Pepper weevil. UC Pest Management Guidelines: Peppers, UC ANR Publication 3460.
For additional agronomic information, please contact your local seed representative. Developed in partnership with Technology, Development & Agronomy by Monsanto.
Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible. ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. The recommendations in this article are based upon information obtained from the cited sources and should be used as a quick reference for information about pepper pest management. The content of this article should not be substituted for the professional opinion of a producer, grower, agronomist, pathologist and similar professional dealing with this specific crop. SEMINIS DOES NOT WARRANT THE ACCURACY OF ANY INFORMATION OR TECHNICAL ADVICE PROVIDED HEREIN AND DISCLAIMS ALL LIABILITY FOR ANY CLAIM INVOLVING SUCH INFORMATION OR ADVICE. 170826144356 101817DME
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