In this section:
Crop monitoring program
Monitoring needs to be based on a realistic, but effective system suited to your farm needs.
Firstly you must be clear about:
- What pests (and diseases) you are monitoring for
- The decisions you want to be able to make using the monitoring results
- The information you need to collect to make these decisions
Then you need a system that enables you to:
- Collect the information easily that you need
- Use it to make decisions
You must also decide if:
- You will manage all of this yourself, include staff, or use a consultant
Pest Monitoring Will Save You Money
Routine spraying without checking pest levels or spray effectiveness is very hit and miss and is likely to result in increased levels of resistance where WFT and whitefly are a problem. Routine spraying is also likely to take more time and money than necessary and give poor results a lot of the time.
Effective pest management depends on identifying changes in pest (and beneficial) insect activity in and around the crop in time to keep damage levels low. Crop monitoring is the only way to gather information and determine the best response to changes in insect levels, including the option of NOT spraying. It is the backbone of reliable crop protection whether using chemical or non-chemical strategies.
Setting up a suitable monitoring program is probably the most complex and time-intensive component of an IPM program, but it is an essential risk management tool for protecting all other investments made in the business. If the initial set-up is done well and then fine-tuned and maintained it quickly becomes highly effective and easier to run.
Simply introducing a good monitoring program will cut crop losses and unnecessary chemical costs and identify hidden weaknesses in the pest control program. Good crop monitoring is absolutely essential if you want to also incorporate beneficial insects into your pest control program.
The notes that follow describe some of the common methods (yellow sticky cards and plant checks) that can be used in a monitoring system and how the information gathered can be used to make decisions, especially for Western Flower Thrips.
What growers have said:
- ThiVu: I do much less spraying now that I check the crop first. I am much happier working in the crop without the chemicals there all the time and I save a lot of time not spraying.
- Emmanual Cafkacis: You got to know what is going on in the crop. Unless you have a good look you can’t tell. I’ve saved a lot of money now that I know what to look for. Its taken out a lot of the guesswork.
Yellow Sticky Traps or Cards
Sticky traps are useful as a way of keeping an eye on flying pests like thrips, whitefly and aphids. They attract these insects because of their colour in the same way that white and yellow flowers do. Thrips are attracted to yellow, blue, and even white. Yellow traps attract thrips, whitefly and aphids. They are very useful for detecting the arrival of these flying insects in the cropping area and can also help to keep an eye on pest levels in the crop. They are also a useful way of sending samples away for identification of thrips species etc. However they do not give a complete picture of pest dynamics in the crop. Adult insects may settle into the crop after flying in and juvenile non-flying stages (eggs, pupae and possibly larvae if coverage is not good) may survive spray applications but will not show up on the traps.
How to use Sticky traps
Sticky traps should be changed or checked at least weekly. They need to be placed just above the growing tips of the plants to catch insects hovering above them and to avoid getting stuck and lost in the crop
How do you check the insects on the cards ?
Sticky traps can be inspected with the naked eye (to get a rough count of the number of different pests), with a hand lens (to be certain how many thrips, whitefly etc), with a microscope (to see what species of thrips or other pests are present). It is important to note and record changes and, if concerned, send traps away for insect identification for Western Flower Thrips.
Changes in pest numbers for different species can be estimated providing important information about the level of threat to your crop and whether or not action is required.
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Whitefly on a sticky trap |
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WALKING THROUGH AND CHECKING CROP PLANTS AND WEEDS
Sampling flowers and leaves in the crop can tell you much more than a sticky trap including:
- The presence or absence and levels of non-flying juvenile stages (eggs, larvae, pupae)
- The presence/absence and levels of non-flying adult insects (mites snails etc.)
- The early stages and extent of pest damage
This information is much more powerful for assessing pest levels, accurately predicting trends and checking the effectiveness of control measures. It is essential for making decisions and following up on the results. It will also reveal a lot about the behaviour of pests and beneficial insects that will help you to manage problem pests. Depending on the pest, where it feeds, hides and breeds you will need to check flowers, leaves, fruit etc. The pattern, frequency and level of sampling depends on the crop, pests of concern and beneficial insects of interest and the time of year.
Checking weeds close to the crop for pest and disease levels
Weeds near to your farm/crop will build up large numbers of pests in spring. Inspecting the weeds can keep you in touch with how the local pest pressure is building up. Better still remove the weeds before the pests build up on them!
