integrated pest management onion … · integrated pest management innovation lab ... at the tip of...

4
Integrated Pest Management Innovation Lab (IPM IL) IPM PACKAGES FOR CROP HEALTH onion O nion, Allium cepa, the second most produced vegetable in the world, originated in the region of Afghanistan, Iran, and Pakistan. It is the most widely grown vegetable crop, and has a wide growth range from the tropics to sub- arctic regions. There are several types of onions grown in the world and they are used both green and dry. This brochure details successful IPM Innovation Lab (IPM IL) approaches for managing onion pests that have been tested by scientists and farmers. Photos and descriptions of key pests of onions are provided. Integrated pest management (IPM), an environmentally-sound and economical approach to pest control, was developed in response to pesticide misuse in the 1960s. Pesticide misuse has led to pesticide resistance among prevailing pests, a resurgence of non-target pests, loss of biodiversity, and environmental and human health hazards. The IPM Innovation Lab has developed and tested robust IPM packages, holistic suites of IPM recommendations and practices for the production of vegetables and other crops. Farmers who use IPM packages in planting, production, and throughout the supply chain see enhanced profitability in their crops. The recommended practices in IPM packages cover economically signifi- cant pest species over a wide range of cropping systems across the trop- ical world, resulting in benefits to human health and the environment. WHAT IS IPM? WHAT ARE IPM PACKAGES? This brochure was created and distributed by the Feed the Future Innovation Lab for Integrated Pest Management (IPM IL). It was made possible through the United States Agency for International Development and the generous support of the American people through USAID Cooperative Agreement No. AID-OAA-L-15-00001 onion package INTEGRATED PEST MANAGEMENT INNOVATION LAB

Upload: vuongkhuong

Post on 30-Jul-2018

216 views

Category:

Documents


0 download

TRANSCRIPT

Integrated Pest Managem

ent Innovation Lab (IPM IL)

IPM PACKAGES FOR CROP HEALTH

onion

Onion, Allium cepa, the second most produced vegetable in the world, originated in the region of Afghanistan, Iran, and Pakistan. It is the most widely grown vegetable

crop, and has a wide growth range from the tropics to sub-arctic regions. There are several types of onions grown in the world and they are used both green and dry. This brochure details successful IPM Innovation Lab (IPM IL) approaches for managing onion pests that have been tested by scientists and farmers. Photos and descriptions of key pests of onions are provided.

Integrated pest management (IPM), an environmentally-sound and economical approach to pest control, was developed in response to pesticide misuse in the 1960s. Pesticide misuse has led to pesticide resistance among prevailing pests, a resurgence of non-target pests, loss of biodiversity, and environmental and human health hazards.

The IPM Innovation Lab has developed and tested robust IPM packages, holistic suites of IPM recommendations and practices for the production of vegetables and other crops. Farmers who use IPM packages in planting, production, and throughout the supply chain see enhanced profitability in their crops. The recommended practices in IPM packages cover economically signifi-cant pest species over a wide range of cropping systems across the trop-ical world, resulting in benefits to human health and the environment.

WHAT IS IPM?

WHAT ARE IPM PACKAGES?

This brochure was created and distributed by the Feed the Future Innovation Lab for Integrated Pest Management (IPM IL).

It was made possible through the United States Agency for International Development and the generous support of the American people through USAID Cooperative Agreement No. AID-OAA-L-15-00001

onion package

INTEGRATED PEST MANAGEMENT INNOVATION LAB

onion diseases identification, descriptions, and images

Black mold(Aspergillus niger)

Post-harvest black discolor-ation at neck and clusters of black spores generally on or between scales. This disease causes the entire bulb to appear black and shriveled.

White rot(Stromatinia cepivora)

White rot causes pre-mature yellowing, wilting, and dropping of leaves, followed by destruction of the root system and rotting of bulbs. Affected bulbs and roots are covered with a thick, white mycelial growth with numerous black or brown colored sclerotia.

Damping off(Pythium spp.)

Infection usually occurs in seedlings and symptoms appear as water-soaked lesions on lower stems and a watery rot that occurs on the roots. Infected tissue becomes soft and constricted at the base, causing the plant to topple. Favored by ill-drained condi-tions or excessive moisture in field.

Purple blotch(Alternaria porri)

A destructive foliar disease favored by cooler climate. Symptoms appear as chlorotic lesions on leaves with concentric black, velvety rings of fungal sporulation. These lesions then girdle leaves causing drying and falling off.

Bulb rot(Fusarium oxysporum)

Yellowing, curling, and necrosis at the tip of leaf blades. Pinkish or reddish discoloration appears at the basal plate of onion. When infected plants are pulled up, the bulb often detaches from the roots.

Pink root(Phoma terrestris)

Infected roots at first turn light pink, then darken through deep pink to red and purple. Roots become semi-transparent, water-soaked, and later shrivel and die. New roots may also become infected. Infected plants become stunted, bulbs shriveled and undersized. Severely infected plants appear to be nutrient deficient. The disease may cause death of plants when infected at the seedling stage.

Downy mildew(Peronospora destructor)

A serious foliar disease, common during cool weather. All plant parts during all growth stages are susceptible to this disease. Primary infection occurs when infected bulb is planted and secondary infection occurs when healthy plants are infected by spores produced by primary stage. Symptoms appear as brown-ish-purple, velvet-like sporu-lation of the pathogen on healthy green leaves, more prominent in the mornings. Later, black mold develops on drying leaves. Infected leaves collapse and die in a short span of time if conditions are favorable.

Iris yellow spot virus

It is a tospovirus that is trans-mitted by onion thrips, Thrips tabaci. It causes straw-colored, dry spindle, or diamond shaped lesions on leaves and scapes. These lesions may have distinctive green centers. Dry, elongated lesions or flecks may resemble thrips injury. Infected seed stalks and leaves may lodge later in the growing season. Plant vigor and bulb size are reduced.

Onion yellow dwarf virus

It is transmitted from plant to plant by the green peach aphid, Myzus persicae, and other aphids in a non-persistent manner Infected leaves show symptoms ranging from yellow streaks to complete yellowing. Leaves are sometimes crinkled and flattened and tend to bend over. Bulbs are usually solid but undersized.

Allium rust(Puccinia porri)

Small white flecks appear on leaves and stem which develop into orange colored circular oval shaped pustules. Heavily infected leaves turn yellow and die premature. Bulb size and quality are also affected.

Onion smut(Urocystis colchici and U. cepulae)

Symptoms appear as dark brown or black thickened lesions on cotyledons and young leaves. Large lesions may cause leaves to curve downward. Raised blister-like lesions may also occur near the base of scales of older plants. Infection progresses inward from leaf to leaf at the base of the plant. Infected plants become stunted and may die within 3-5 weeks after emergence.

Photos (From left):• Onion white rot• Iris yellow spot

virus• Pink root

Source: omafra.gov.on.ca Source: bugwood.org Source: Oklahoma State University

Soil preparationPreparing the soil before planting results in healthy plants with minimal pest problems. Soil solarization and fertilization combined with compost inoculated with Pseudomonas fluorescens, Trichoderma spp., neem cake, and Vesicular Arbuscular Mycorrhiza (VAM) fungus improves the nutrient availablity, priming the plant’s own defenses and reducing the incidence of soilborne pathogens.

Bulb selectionSelection of healthy bulbs is important in raising a healthy crop as bulb rot caused by Fusarium is a major challenge in the early crop growth stage. Healthy bulbs should be selected from stored seed onion before planting.

Bulb treatmentTreating bulbs with the Trichoderma spp., Pseudomonas fluorescens, and Bacillus subtilis protects seedlings from fungal diseases especially bulb rot. Additionally, these treatments increase seedling vigor and induce plant defense against pests.

Trap/Barrier cropsCastor (Ricinus communis) can be used as a trap crop for Spodoptera litura. Growing maize as a barrier crop is effective in preventing the entry of onion thrips into an onion field.

Crop RotationCrop rotation with non-host crops also helps in reducing incidence of soil-borne diseases.

FertilizationNeem cake or mustard oil cake alone, or in combination with compost inoculated with Trichoderma spp., is effective against soil-borne diseases. Additionally, they help build-up of beneficial soil microbes that assist in nutrient absorption by the plants. A proper nutritional balance, such as adequate calcium and nitrogen, helps in reducing thrips populations.

MulchingMulching conserves moisture, harbors natural enemies, and reduces insect pest, mite, and disease incidence. Mulching, especially straw mulch, is helpful in reducing thrips population and improving crop growth.

Onion thrips(Thrips tabaci)

A polyphagous pest feeding on more than 300 plant species. Thrips feed on leaves by rasping and sucking cell contents causing a silvery sheen or streaks on leaves. Several topsoviruses, such as Iris yellow spot virus, are transmitted by onion thrips and are responsible for serious economic losses.

Black onion aphid(Neotoxoptera formosana)

Forms dense colonies on leaves and reduces value of crop due to feeding (sap sucking) and physical presence of aphids on leaf onions.

Beet armyworm(Spodoptera exigua)

A major pest on vegetable crops with a wide host range. Young larvae feed inside the leaves, leaving only the outer cuticle and causing a charac-teristic “window-paning” on leaves.

Army worm(Spodoptera litura)

A polyphagous pest that feeds on a wide host range of crops including the families Solanaceae, Malvaceae, Brassicaceae, Fabaceae, and others. Early larval instars feed in clusters, skeletonizing the leaves.

Leafminers(Liriomyza spp.)

Tunneling of leaves by larvae results in thin white trails/mines on leaves, causing reduced photosynthesis and yield.

Onion fly(Delia antiqua)

Serious pest of onion and other related allium crops. Larval feeding on the roots/base of the plant leads to distorted growth of bulbs and rotting of tissues. Young seedling may wilt and die due to larval feeding. Often the bacterium Bacillus carotovorus enters the maggot damaged areas and causes soft rot.

onion pests identification, descriptions, and images

onion ipm techniques

Photos (From left):• Black onion aphid• Onion fly

Source: bugwood.org Source: growveg.com

onion ipm technologies

Sticky trapsSetting up sticky traps of different colors, materials, and shapes in the field have been helpful in reducing pest populations such as thrips and adult leafminers.

Biological ControlSome of the common parasitoids, such as Chelonus insularis, Cotesia marginiventris, and Meteorus autographae, occur naturally in the field, and conservation biological control is effective against Spodoptera.

Pheromone trapsSex pheromone traps are useful for monitoring and management of armyworms, Spodoptera spp.

Botanical pesticides Neem oil, neem seed kernel extract, and commercial formulations of azadirachtin are effective in controlling insect pests, especially caterpillars.

Microbial biological control agentsIn addition to the use of nuclear polyhe-drosis viruses (NPVs) against Spodoptera litura, formulations of the fungi Verticillium, Paecilomyces, Metarhizium, and Beauveria species and parasitic nematodes such as Heterorhabditis sp. and Steinernema sp. may be used for the control of armyworms and other insect pests. Pseudomonas flourescens and Trichoderma viride are effective against Fusarium spp. Microbial control agents have little to no impact on parasitoids and predators of pests. For this reason, natural enemies will continue to serve as effective regulators of a variety of pests. By using these biopesticides, one may totally eliminate the use of synthetic pesticides and thus produce crops free from chemical pesticides for consumers.

The Integrated Pest Management Innovation Lab (IPM IL) develops sustainable and economical pest control methods to improve livelihoods for farmers worldwide. Our eight projects in seven countries work with scientists, extension agents, students, and farmers in the tropical and subtropical world.

We are funded by USAID and housed at Virginia Tech in Blacksburg, Virginia.

Contact us:Office of International Research Education and Development (OIRED)Virginia Tech526 Prices Fork RoadBlacksburg, VA 24061540-231-3516 | [email protected]/IPMIL

FOR MORE INFORMATION

Photos (source: IPM Innovation Lab) (Clockwise fom top left):• Mini model of onion IPM module demonstrated to farmers• Farmer with harvested onion from IPM and non-IPM plots• An onion thrips-infested shallot field with burnt-up appearance

Prepared by Dr. Jaspreet Sidhu, IPM Innovation Lab