Kerusakan oleh OPT

Crop LossesCrop Losses

Constrain Affecting Crop Yield

Level Constrain

Pest

• an organism to be considered a pest when a

damaging stage of the organism present in

high enough numbers to cause actual injury to

something valued by people.something valued by people.

• a species with its population and age

distribution at a given time and place causes a

human valuation of item being injured or

damaged.

• Major crop productivity constrains :

- Abiotic or physical pressure (example: unfavorable

climate, unsuitable soil condition)

• - Biotic pressure (example : pests, pathogens, weeds

or any organism that interferes with the activities

and desires of humans)

• Pests are all organisms within the cropping• Pests are all organisms within the cropping

environment that cause injury to the crop and are

capable of reducing yield and/or quality

• Organisms that cause economic damage are the

ones of interest in pest management and crop

protection

Pest StatusKey pests : OPT utama yang paling penting karena

sangat merusak atau merugikan

Minor pests : OPT yang tidak prlalu merugikan

enting karena tidak te

Secondary pests : OPT yang hadir (menginfeksi)

setelah terjadi kerusakan oleh OPT sebelumnya

Occasional pests : OPT yang hanya muncul dan

merugikan kadang-kadang saja

Potential pests : OPT yang karena kemampuan

berkembangnya meningkat dikawatirkan akan

menjadi outbreak

• Chronic pests : OPT yang selalu ada disetiap musim dan

semakin lama perkembangannya bisa semakin

meningkat

• Migrants : OPT yang datang dari daerah lain karena

adanya perbedaan lingkungan atau jenis inang

• Accessory Species : jenis yang tidak (belum) sebagai

OPT karena cara hidup atau populasinya tidak merusak OPT karena cara hidup atau populasinya tidak merusak

tanaman

• Vectors (Pest status often linked with pathogen)

Alternate Hosts : Hama (serangga) yang menularkan

patogen dan mempunyai hubungan spesifik dengan

patogen tersebut

• Carier : Serangga (atau binatang lain) yang menularkan

patogen tetapi tidak mempunyai hubungan spesifik

Status of pest is determined by several

factors• Pest species must be present at the right stage

• Crop must be a susceptible variety and growth

stage

• Environment criteria must be met.• Environment criteria must be met.

• Time must occur at the same time.

• Pathogen – Host – Environment triad must all

be right in order for an outbreak of disease.

• When Pest – Crop – Environment right at the

same Time, leads to “damage”.

Injury vs Damage

• Injury – The effect that the pest has on the

crop or commodity.

• Damage – The effect that injury has on man’s

valuation of that crop or commodity.valuation of that crop or commodity.

• For crops, “Injury” is biological and “Damage”

is economic. For non-crops, “Injury” =

“Damage”.

• Pests are often classified by the type of injury

that they cause:

• Direct Pests (removal of plant tissue such as

foliage, sap)foliage, sap)

• Indirect Pests (e.g. Disease vectors)

• Medical/Veterinary

Crop Losses

• Crop injury by pests results into crop damage

that we often estimate in term of crop loss

(yield loss or economic loss)

• Example: a leaf roller removes 30% of banana • Example: a leaf roller removes 30% of banana

leaf tissue (injury), and this results into 35%

reduction of banana yield (damage).

• CROP LOSS: reduction in either quantity or

quality of yield or difference between actual

yield and yield obtained in absence of disease

• YIELD: measurable produce of a crop (seed,

fruits, leaves, tubers etc)

• Disease and crop loss assessments are • Disease and crop loss assessments are

necessary for evaluating the economic impact

of a disease and the benefit of particular

control strategies

• Crop loss assessment is usually considered as

part of plant disease epidemiology

• the assessment of disease is the amount of

disease that is present

• can be measured as the proportion of a plant

community that is diseased (disease

incidence) or as the proportion of plant area

that is affected (disease severity)

• Easier diseases to assess are those that kill

whole trees in orchards or plantations, and

those that destroy the actual harvested

product, such as fruit or grain

• The growth of the crop, its yield potential, the

development of the disease and its impact on

yield all have to be measured to predict the

impact on yield of particular levels of diseaseimpact on yield of particular levels of disease

Assessment of the effect of disease on crop yield

normally involves five steps

• developing a descriptive growth stage key for the

particular crop species

• developing methods to assess the incidence and

severity of disease

• developing statistically sound methods of sampling crop • developing statistically sound methods of sampling crop

populations for assessment of the amount of disease

• estimating the negative impact of particular levels of

the disease on crop yield and quality, and

• evaluating the economic benefit from various methods

available for reducing the amount of disease.

Curve of product value vs injury

Maximum value

Value

Injury

Species 1

Species 2

Economic damage

Losses caused by pest

World Agricultural Cake of plant losses

Corn losses due to diseases

Rice Losses due to pests and diseases

Brown Rice Plant Hopper, very

important pest of rice

Rats damage rice in the field and

post harvests

Cabbage Losses due to pests and

diseases

Chili Losses due to Pests and

Diseases

Sugarcane losses due to pests and

diseases

Cacao Losses due to Pests and

Diseases

Kerusakan setelah panen

(Post Harvest Losses)

• External Factors Which Lead to Postharvest

Losses :

- Mechanical Injury

- Parasitic Diseases- Parasitic Diseases

Mechanical Injury

• Fresh fruits and vegetables are highly

susceptible to mechanical injury owing to

their tender texture and high moisture

content. Poor handling, unsuitable packaging content. Poor handling, unsuitable packaging

and improper packing during transportation

are the cause of bruising, cutting, breaking,

impact wounding, and other forms of injury in

fresh fruits and vegetables.

Parasitic Diseases

• The invasion of fruits and vegetables by fungi,

bacteria, insects and other organisms, is a major

cause of postharvest losses in fruits and

vegetables. Microorganisms readily attack fresh vegetables. Microorganisms readily attack fresh

produce and spread rapidly, owing to the lack of

natural defense mechanisms in the tissues of

fresh produce, and the abundance of nutrients

and moisture which supports their growth

Internal Factors

• Physiological Deterioration

• Fruit and vegetable tissues are still alive after harvest, and continue their physiological activity.

• Physiological disorders occur as a result of mineral deficiency, low or high temperature injury, or deficiency, low or high temperature injury, or undesirable environmental conditions, such as high humidity.

• Physiological deterioration can also occur spontaneously owing to enzymatic activity, leading to over ripeness and senescence, a simple aging phenomenon.