Title: Principles of IPM: Monitoring Methods

Learning Objective: To learn the various methods of monitoring pest in an IPM program.

Materials: Presentation board (chalk board or flip chart) or slide projector, chalk or pen, pheromone traps, hand lenses, counters, sweep nets, field sites and lesson fact sheet.

Time Needed: 6 hours

Power Point Presentation: Lesson 3 (computer file: lesson3.ppt)

Opening: Emphasize that the underlying principles of pest control are that no control measures should be taken against a pest unless it is known to be present and no control measure should be taken unless it is known the pest is in significant numbers to cause economic damage. Briefly discuss the logic of these two principles.



A. Importance of Monitoring

1. To assess the pest situation and determine what sort of pest activity is


2. For decision making

3. To predict pest problems before they occur

B. Monitoring Techniques and Procedures

1. Monitoring guide lines

a. What to look for:

i. presence and evidence of pests

ii. evidence of damage

- nature of damage

- where the damage is found

- are there still pests present in the damaged area

iii. presence of natural enemies

iiii. evidence of potentially contributing activities to the

pest problem

Examples: Human activities such as poorly

managed waste or crop residues contributing to the

problem; a microclimate created by a valley or

slope, which provides a favorable environment to a


iiii. if unrecognized pests are found, samples should be

collected and brought to the county extension office.

b. Frequency of monitoring:

i. determined by the biology of the pest

ii determined by the crop, if a crop has a low threshold of

damage, more intensive monitoring may be needed.

iii at regular intervals (weekly and maybe more frequently

when a pest approaches a borderline to becoming a threat

to a crop)

c. Size of area to monitor:

i. depends on the crop, the farm size, and the pest

ii. enough to provide good field representation or coverage

iii. depends on the degree of accuracy required and the

resources available

iiii. the field is surveyed in a pre-arranged pattern, such as

walking in an S, U, Z, V or X shape

d. record keeping:

i. accurate records are important for decision

making and for evaluating trends in pest populations

season to season

ii. if a monitoring form is developed, it should provide

information on:

- both harmful and beneficial insects

- identification of the field and the sample date

- sample method

- units of sample, e.g. insects per tree, infected fruits per


2. Monitoring methods

a. Types of monitoring techniques

i. visual counts over a representative area

- counting the number of pests present per plant, per leaf,

per fruit, per terminal, per area bases

- damage counts which estimate pest population per plant,

per area or per fruit (pre and post harvest)


ii. pheromone traps

- sticky traps which use pheromone bait to attract insects

iii. sweep nets

- need to use a standardized sweep

- sampling locations need to be consistent

- in some cases sampling times need to be consistent

iiii. field history, look for patterns of pest problems.

b. monitoring for insect pests

i. visual counts

ii. sweep nets

iii. pheromone traps

c. monitoring for diseases

i. visual counts

ii. field history

d. monitoring for weeds

i. field history

ii. visual counts

e. monitoring for others

i. visual counts

ii. field history


1. Monitoring method for insect pests of cucurbits: Check fields twice per week by examining 50 plants per field when plants are small (up to 10 leaves) and as plants get larger, change the sampling plan to 100 leaves per field. The samples (either 50 plants(early season) or 100 leaves (mid to late season)) should be taken so that all areas of the field are represented. The monitoring should start at a corner of the field, walking in an X or Z pattern (Cartwright, no date)

2. Monitoring method for weeds in onions: Walk the field and record on a map or sketch of the farm where the weeds are prevalent. Also report the species of weeds, if it can be easily determined, or at least whether the weeds are annual or perennial grasses, annual or perennial broadleaf weeds, or sedges. Report the size of each weed species as follows:

<1" (<2.5 cm) in diameter

>1"(>2.5 cm) in diameter

Estimate the density of weed cover on a scale of 0 to 5, where 0= none and 5= many. You may need to walk additional areas of the field to obtain a realistic weed picture. If very few or no weeds are seen, scratch the top 1" (2.5 cm) or soil away and look for white threads at a few locations. These "threads" represent the first stages of weed seed germination.(Hoffmann et. al., 1996)




Cartwright, B. No Date. Management of Insect and Mite Pests of Cucurbits. In: Cucurbit Production and Pest Management. P. 22. Oklahoma Cooperative Extension Service Publication E-853


Hoffmann, M.P., C.H. Petzoldt, and A.C. Frodsham. 1996. Integrated Pest Management for Onions. Cornell Cooperative Extension. 78 pp.


Olkowski, W., S. Daar, and H. Olkowski. 1991. Common-Sense Pest Control. Taunton Press, Newtown, CT. 715 pp.


Watson, T.F., L. Moore, and G. W. Ware. 1976. Practical Insect Pest Management. W. H. Freeman and Co., San Fransisco. 196 pp.


Practice monitoring in the field.

Using hand lenses, counters, and sweep nets, scout for pests in a few fields on the island. To make the most of this exercise, the field location should be a place with known pest problems and that has a wide variety of problems