Integrated pest management of potatoes

doi:10.4236/as.2011.23039

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Vol.2, No.3, 297-300 (2011) Agricultural Sciences

doi:10.4236/as.2011.23039

Integrated pest management of potatoes

Y asa r Alptekin

Department of Plant Protection, Faculty of Agriculture, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey;

*Corresponding Au thor: yasar.alptekin@gmail.com

Received 14 April 2011; revised 23 May 2011; accepted 28 July 2011.

ABSTRACT

The potato (Solanum tuberosum L.) is the most

important dicotyledonous source of hu- man

food. It ranks fifth major food crop of the world,

exceed only by the grasses such as wheat, rice,

maize, and barley. It is characte- ristically a crop

of the cool, temperate regions or of elevation of

approximately 2000 m or more in the tropics. It

requires cool nights and well drained soil with

adequate m o istu re a nd do es n o t p r o duc e well in

low altitude, warm, tropical environment. Com-

mercial production of most potatoes is primarily

through vegetative propagation by means of

lateral buds formed on the tuber, a modified

stem. T rough such veget ative prop agation, many

diseases are transmitted from generation to

generation. Suppression of such diseases and

reduction of yield losses due to disease are a

necessary part of increasing the food supply.

The principles, strategies, and tactics of plant

disease management are important to preven-

ting yield losses. Integrated pest management

(IPM) may supply effective control of the potato

pests includi n g ap hids (v ec tor o f some virus es),

Verticillium wilt blackleg, bacterial ring rot,

Rhizoctonia, Phytophthora infestans (late blight)

and several weeds (night shades, pigweeds,

lambs quarters, and annual grass es). It includes

regular inspection for healthy seed or nursery,

crop production, correct identification of the

problem, cultural practices (crop rotation, sani-

tation etc.), biological control, soil fumigation (if

necessary), seed or nursery stock treatment

and disinfestations of cutting tools. In this re-

view, pest management methods of potatoes

included in IPM was summarized.

Keywords: Potato; IPM; Pests and Diseases

1. PEST MANAGEMENT PROGRAM

No single management program is suitable for all po-

tato crops. Pest problems vary from field to field and

season to season because of differences in soil type,

cropping history, cultural practices, cultivar, and the na-

ture of surrounding land. Choice of market and market

conditions also affect the feasibility of management op-

tions because they determine how a crop must be han-

dled and the value of that crop. Regard less of conditions,

however, four components are essential to any IPM pro-

gram: 1) Accurate pest identification 2) field monitoring

3) control action guidelines 4) effective management

methods [1].

Because most pest management tools, including pesti-

cides, are effective only against certain pest species, one

must know which pests are present and which are likely

to appear. Different control methods may be n eeded even

for closely related species.

By monitoring his field, one can get the information

he needs to make management decisions. Monitoring

includes keeping records of weather, crop development,

and management practices, as well as evaluating inci-

dence and levels of pest infestations.

Control action guidelines indicate when management

actions, including pesticide applications, are needed to

avoid losses due to pests or other stresses. Guidelines for

most pathogens and weeds are usually based on the his-

tory of a field or region, the stage of crop development,

observed symptoms or damage, weather conditions, and

other obse r vat i on s

2. MANAGEMENT METHODS

2.1. Seed Quality and Certification

A number of pests can be transmitted in infected seed

tubers, including bacterial ring rot, blackleg, common

scab, late blight, potato viruses, powdery scab, Rhizoc-

tonia, root knot nematodes, silver scurf, and wilt dis-

eases. In order to prevent these problems, one must start

with healthy stock [2]. Stem cutting and micro-propaga-

tion techniques have been developed to obtain pest-free

potato plants for propagation and production of certified

seed tubers. Disease-free stem cuttings or tiny pieces of

Y. Alptekin / Agricultural Science 2 (2011) 297-300

298

meristem tissue are cultured and propagated under sterile

conditions to produce large numbers of disease-free

plantlets or mini tubers. Several generations of plants are

grown in the field to produce certified seed tubers that

will be sold to commercial growers [3].

Extra precautions are taken to reduce the incidence

and spread of pests in fields where seed potatoes are

grown. Most seed potatoes are grown in cool, short sea-

son areas where pest populations, including vectors of

potato viruses, remain low and the symptoms of infected

plants easier to recognize. Ideally, seed fields are iso-

lated from commercial fields and home gardens from

which potato viruses could be transmitted by aphids.

2.2. Biological Control

Any activity of a parasite, predator, or pathogen that

keeps a pest population lower than it would be otherwise

is considered biological control. One of the first assess-

ments that should be made in an IPM program is the

potential role of natural enemies and hyperparasites in

controlling pests. Control by natural enemies and hy-

perparasites is inexpensive, effective, self-perpetuating,

and not disruptive of natural balances in the crop eco-

system.

Natural enemies that affect nematodes, weeds, and

fungi are being studied, but as yet no practices are rec-

ommended for improving biological control of these

pests. Bacteria antagonistic to Erwinia caratovora are

being developed as seed piece treatments for reducing

seed piece decay and blackleg. Among rhizobacteria

Agrobacterium radiobacter, Bacillus subtilus and Pseu-

domonas spp. are antagonistic to potato cyst nematodes

(Globodera pallida and G. rostochiensis although Pas-

reuria penetrans attach PCN [4]. Larkin [5] reported that

soil-application of aerated compost tea (ACT) and the

combination of ACT with a mixture of seven different

mycorrhizal fungus species belong to Glomus spp. re-

duced stem canker, black scurf, and common scab on

tubers by 18% - 33% and increased yield 20% - 23% in

the barley/ryegrass rotation, but not in the other rota-

tions.

2.3. Resistant Cultivars

Plant breeding is one of the most powerful tools av ail-

able for both the management of pests and the produc-

tion of the best crop. Pest management is one of many

factors that must be taken into account when choosing

cultivars. Cultivars resistant or tolerant to disease can

help reduce losses caused by some soil-borne pathogens

and provide long-term, economical protection from con-

ditions that otherwise could inflict severe losses every

season.

Part of ever y breeding program is the search for resis-

tance to serious diseases, disorders, and nematode pests.

Resistance to insect pests is being investigated. New

potato breeding selections are assessed for resistance to

several viruses, leaf-roll net necrosis, root-knot nema-

todes, Verticillium wilt, scab, blackleg, early blight, and

several physiological diso rd er s [6] .

2.4. Chemical Control with Pesticides

Properly used, pesticides can provide economical

protection from pests that otherwise would cause sig-

nificant losses. In many situations, they are the only fea-

sible means of control. Careless or excessive use of pes-

ticides, however, can result in poor control, crop da-

mage, higher expenses, and hazards to health and envi-

ronment. In an IPM program, pesticides are used only

when field monitoring indicates they are needed to pre-

vent losses.

Fungicides can reduce damage caused by certain

foliar pathogen such as powdery mildew, late blight, and

severe early blight. To be effective, they usually must be

applied before infection occurs or when the disease just

begins to develop. Soil fumigants may be used to control

nematodes or Verticillium.

3. CULTURAL PRACTICES

Proper management of the potato crop, from field

preparation and planting through harvesting and storage

is essential for maximum yields of high quality tubers.

Many cultural practices including seed selection and

handling, planting, irrigation, fertilization, vine killing,

careful harvesting methods have a significant impact on

pest damage. Even when you cannot choose cultural

methods solely for their effect on pest management, it is

important to understand their impact on pests so that you

will know what to expect.

Careful water management helps prevent Rhizoctonia

and piece decay early in the growth of the plant, reduces

tuber malformation and symptoms of Verticillium wilt

during the season, the severity of scab, and helps prevent

tuber rots as plants mature and die. Excess fertilization

of indeterminate cultivars delays tuber growth and may

reduce yields [7]

3.1. Sanitation

Sanitation is essential to the prevention of seed piece

infection during cutting and handling, and prevention of

spread of the pathogens in contaminated soil, water, and

field equipment. Strict sanitation requirements must be

followed in growing seed potatoes.

Any potato cull piles shou ld be destroyed or sprayed

to ensure that no Phytophthora sporangia will be blown

Y. Alptekin / Agricultural Science 2 (2011) 297-300

299299

from there to the potato plants in the field later on. Cull

potatoes are excellent hosts for potato diseases and can

provide a safe haven for potato insects to increase in

numbers. Important pests that can be harbored in waste

potatoes include late blight, potato leaf roll virus (PLRV),

bacterial ring rot, and nematodes. Soil associated with

cull potatoes can be infested with pests su ch as powdery

scab, nematodes, and weed seeds. Waste potatoes must

be handled correctly to eliminate these and other poten-

tial dangers [8]. Tubers are cut with disinfested knifes to

reduce spread of ring rot among seed pieces and the seed

pieces usually treated with a fungicide, a bactericide, and

an insecticide to protect them from pathogens on their

surface or in the soil [2].

3.2. Crop Rotation

Proper crop rotations enhance soil fertility, maintain

soil structure, reduce certain pest problems, increase so il

organic matter, and conserve soil moisture [3]. Generally,

most useful rotations for potato fields are forage crops

and grains, including corn. Crop rotation is useful for

control of soil-inhabiting pathogens that have limited

host ranges and require host plant residues for survival.

Rotation is less effective for pathogens such as Verticil-

lium spp. or Phytophthora erythroseptica, which can

survive in the soil fo r a long time in the absence of host.

It is best not to follow a potato crop with another, and

rotation with legumes, corn, or other unrelated crops will

reduce the population of potato pathogens. Soil popula-

tions of beneficial culturable bacteria and overall micro-

bial activity which is suppressive to potato pathogens

tended to be highest following barley, canola, and sweet

corn rotations, and lowest with continuous potato [9].

3.3. Seed Treatment

Seed piece decay frequently involves a Fusarium

fungus acting synergistically with bacteria. Therefore,

chemical seed treatments, which primarily act as fungi-

cides, are useful when conditions favor development of

Fusarium on seed pieces.

3.4. Irrigation

Availability of soil water is a major factor that deter-

mines yield and qu ality of the potato crop. To o little wa-

ter will reduce yields, induce tuber malformations, or

increase severity of scab or Verticillium with symptoms.

Excess or poorly timed irrig ation may reduce yield or in

storage or leach nutrients from root zone. Fluctuations in

water availability favor disorders such as second growth

and internal necrosis.

Sprinkler systems provide the most flexibility and

most efficient water application, and fertilizers and some

pesticides can be applied through sprinklers. Sprinkler

irrigation provides conditions in the canopy that are fa-

vorable for certain diseases such as early blight, late

blight, and white mold (Sclerotinia spp.). To reduce

spread of these diseases, foliage should be allowed to

dry out between irrigations.

3.5. Fertilization

Adequate nutrient availability throughout the growing

season is necessary for the best yield and quality. If nu-

trient deficiencies occur during tuber growth, the plant

shunts nutrients from the stems and leaves to the grow-

ing tubers, thereby hastening aging of the vines and

yields are reduced. On the other hand, excess fertilizer

delays the onset of tuber growth in indeterminate culti-

vars and may reduce their yields; tuber decay after har-

vest may also be increased an d processing qualities such

as specific gravity may be lowered.

3.6. Harvest

Before harvest, the infected vines must be killed with

chemicals to destroy late blight inoculum that could be

in contact with the tubers when they are dug up [2].

Prevention of bruising is one of the most important

considerations in a well managed harvest operations.

Blackspot and shatter bruise can seriously affect marke-

table yield if precautions are not taken to reduce them

[3].

3.7. Sprout Inhibitors

Sprout inhibitors should be applied to fresh market or

processing potato tubers that are to be stored for more

than 2 to 3 months. Low storage temperature cannot be

used to prevent sprouting without undesirable accumula-

tion of sugars. Foliar applications of sprout inhibitors are

used: One, maleic hydro z ide, is app lied to potatoes while

they are still actively growing; the other, chlorpropham

(CIPC), is applied through the ventilation system in

storage. These sprout inhibitors should never be applied

to seed potatoes.

3.8. Storage

A large part of the crop in most growing areas is

stored for fresh market or processing during the winter

and spring. Design can vary but most storage facilities

have controls for temperature, humidity, and ventilation.

Ventilation is essential during storage. It removes heat

and excess moisture that may condense on colder tubers,

and heat produced by respiration; at the same time it

helps provide even temperature and humidity within the

storage area and oxygen to support tuber respiration.

Y. Alptekin / Agricultural Science 2 (2011) 297-300

300

Uniform airflow throughout the pile is important.

REFERENCES

[1] Fry, W.E. (1982) Principles of disease management. Aca-

demic Press, Cambridge, 378.

[2] Agios, G.N. (1997) Plant Pathology. 4th Edition. Aca-

demic Press, Cambridge, 229.

[3] Anonymous (2008) UC IPM pest management guidelines:

Potato UC. ANR Publication, New York.

[4] Kerry, B., Barker, A. and Evans, K. (2003) Investigation

of potato cyst nematode control. Nematode Interaction

Unit, Plant-Pathogen Interaction Division, Rothamsted

Research, Harpenden Herts, AL5 2JQ No. HH3111TPO,

87. http://programs.cphst.org/pcn/

[5] Larkin, R.P. (2007) Relative effects of biological amend-

ments and crop rotations on soil microbial communities

and soil-borne diseases of potato. Soil Biology and Bio-

chemistry, 40, 1341-1351.

[6] Hooker, W.J. (1983) Compendium of potato diseases.

The American Phytopathological Society, St. Paul.

[7] Rich, A.E. (1983) Potato diseases. Academic Press, Cam-

bridge, 1-2.

[8] Olsen, N., Nolte, P., Harding, G. and Ohlensehlen, B.

(2001) Cull and waste potato management. University of

Idaho, College of Agriculture, Cooperative Extention

System CIS Bulletin # 814.

[9] Karkin, R.P. (2003) Characterization of soil microbial

communities under different potato cropping systems by

microbial population dynamics, substrate utilization, and

fatty acid profiles. Soil Biology and Biochemistry, 35,

1451-1466.