Learn About Scouting for Pests

What is Scouting?

What is Scouting? Let me answer that by calling it something else like “looking carefully,” “monitoring,” or “investigating.” And let me couple that with record-keeping and data collection. Whatever I call it, or more importantly whatever you call it, it is without a doubt one of the cornerstones which separates good growers from those wanting to be good growers. In other words, while not trying to be too critical, if you grow plants for a living, or do so in any other capacity other than as a home gardener, you really need to incorporate scouting into your agenda — your livelihood depends on it. I know, you’re busy enough already, but without a regular scouting regimen, a lot of what is crowding your schedule is probably the result, either directly or indirectly, of not scouting. Whew. Now that that’s off my chest I can delve into the details of this butt-saving, ritualistic duty.

What’s it Take?

What does it take to scout? Figure about twenty minutes per week per one-thousand square feet of crop area in greenhouses and other interiors-and for large, outdoor applications, by way of area sampling, figure about the same amount of time per week per acre. Out of pocket costs will equate almost solely to whatever your scout gets paid for the amount of time specified. Additional expenses will be for other necessary tools for the scout: clipboard, paper, a pen or pencil, sticky traps (or sweep net for outdoor use), a magnifier or hand lens, plant tags or similar markers to identify specific plants and a raw potato (if needed, and I’ll explain so please read on). With exception to the cost of labor-and your scout should be well compensated-the outlay is negligible.

Job One

Scout's Tool Cart One of the first duties for your hired gun (or you, maybe) is to put on paper the areas which need scouting attention. In other words make some maps (see an indoor and outdoor Scouting Map example shown on the Scouting Plan page). These maps need to be permanently numbered or labeled by area. You may choose structure names or greenhouse numbers-or for interiorscapes, account names — and for field settings, try field numbers or something identifiable to you and your scout. These maps should have spaces for information like the date, square foot (or acreage), crop specs, and comments about what was found and how it was corrected or dealt with. After all the permanent information has been drawn on the map it should then be copied so that one copy per map can be used for every scouting venture.

To be Effective

Scouting, in order for it to be truly effective, should be performed as outlined by a predetermined schedule. This schedule should consider several factors because it should not be changed during the season; the scout and management, plus all other concerned parties, should be allowed into the decision-making process as it pertains to scheduling. Dedicated scouting once a week should be sufficient in most operations. Dedicated as in it shouldn’t be done during watering or harvesting or any other duty which would split the focus of the scout. And the day of the week should be unalterable. This is important and needs your consideration and commitment because record-keeping is a major part of a good scouting program. The day of the week finally chosen is important. For instance, let’s say Tuesday is scouting day-and Tuesday is a good day from the point of view that good bugs may need to be ordered in time for the following week and most biocontrol distributors have and enforce deadlines. (A day early in the week may be of lesser importance if biocontrols are not your preferred method of control.) However, if the day is Tuesday one week and Thursday the next, the numbers being recorded will be skewed and will not reflect actual trends. How many bugs did you count last week? Yeah, the week with nine days in it! How ’bout the week before? Yeah, that week had five days in it! Do you see the point here? Mondays and Fridays should be avoided for several reasons: too much drinking during the weekend could degrade your scout’s Monday vision; and by Friday he or she may be rushing to get outta’ there. Moreover, due to long weekends and such, interruptions to the program will be more probable. Still on the topic of scheduling, the time of day also plays a role: the lighting in the area to be scouted should be good so the scout can see properly — and the scout should have good eyesight (Mr. Magoo would be a poor candidate). High noon might be a good time: the lighting is good and many of the pests you’re looking for should be active.

How’s it Done

Okay. Now that the mapping is done and the schedule has been determined, let’s get into the how-to. Indoors first, in a greenhouse for this example: Divide the greenhouse into sections and mark them. This information will transferred onto the map. Crop information should also be added per section, unless the entire greenhouse is used for the same crop (a monoculture). Now, parts of each section, such as benches, should also be identified and marked. Each section, in a smaller greenhouse, up to five thousand square feet more or less, should be of about 250 square feet in size. This type of organization should facilitate good scouting. Larger greenhouses may use larger sections of about a thousand square feet, assuming there is not too much crop diversity clouding the uniqueness of each section. In each section there should be one three-by-five (or bigger in larger installations) yellow sticky trap (if thrips are the only pest being scouted for, or there are certain biocontrol agents being used, a blue trap made be substituted for the yellow). The trap in each section should be mounted two to three inches above the plant canopy and in such a way that it can be easily accessed for detection and counting. It should also be fixed with the flat side against the horizontal flow of air so it will likely capture more pests. Another trap, if fungus gnats are a target pest, should be placed sticky side up on the medium (when it is ruined or used up it can be flipped over). Again using only one per section. In either case, traps should not be placed where they will be disturbed by workers. If it is not practical to put a sticky trap on the medium, a quarter-inch slice of raw potato placed on the medium will trap the larvae of these pests and facilitate easy detection and counting.

Modus operandi

The scout, at the predetermined time during the day chosen for this activity, should enter the greenhouse and, starting from section one, check the trap(s) and potato slice, if used, in that section. The numbers and types of critters detected should be counted and recorded. The traps should be changed frequently to facilitate easy counting. If little is captured, the trapped bugs may be circled with a pen so they are not counted again the following week (and you can kiss the pen good-bye as it will never be useful on paper again). In each section a plant or plants representative of the plants in that section should be marked or tagged. This plant, on the surface, should be inspected thoroughly starting at the growing tip and continued downward toward the pot or medium’s surface. Then the same plant, inward toward the main stem, should be inspected from the pot or medium’s surface upward toward the tip. If it is possible, the root-ball should be pulled out of its container and inspected, too. All information should be recorded, including signs of pest and biocontrol agent activity, disease symptoms and any other anomaly which may indicate a problem or condition. Good news is desirable to management so don’t forget to include positive signs as well. The section at this point is done until the following week, so it’s time to move on to the next, repeating all of the aforementioned activities. Larger greenhouses will employ the same strategies, just on a larger scale — a thousand square feet per section as described in the last paragraph.

Scouting Interiorscapes

An interiorscape should be done in pretty much the same manner as is done in a greenhouse. Differences may include the exclusion of sticky traps since these places are usually open to the public. Traps can be a minor, though sometimes amusing, hazard to people if they get their hair stuck on them. They can also be unsightly. Depending on the size of the planting display, the traps may be able to be hidden and placed out of harm’s way. Potato slices can still be a very handy indicator tool. And specific plants can still be identified and marked (even if they are marked only on the map). Otherwise the same organized regimen should still be employed. The rules do not change very much-unless the account is visited on a biweekly schedule for regular maintenance-and the principles will always be the same.

And Outdoors

Ironically the rules do not change very much in outdoor applications — though weather can alter your schedule significantly. Instead of using traps, the scout will be wielding a sweep net (which is not really a net but a muslin bag held open with a spring steel hoop attached to a handle. Its shape will be that of a child’s butterfly net, though bigger and more durable). The field will be labeled on the map and will have specific sections identified and marked, with particular attention being paid to the field’s periphery and areas of abutment with neighboring wild areas and other fields and crops. Each section will be entered and swept. By sweeping the scout will lightly move the net through the foliage of the plants. He or she will then dump the contents of the sweep net into a bug-tight box or collection unit. This box will probably be marked and taken back to a more controlled environment so its contents can be sorted, identified and counted. Sticky traps should not be used as they will be used up too quickly and will be of little use. And potato slices will probably be eaten by animals. Again, the principles will always be the same.

In Summary

In any situation described herein, the actions which follow will be the same: the map or maps will be taken back to a central point and analyzed and, perhaps, discussed with management. Curative actions, if any, will be prescribed and recorded on the map for historical reference and as a guide for the curative action performance (which, if biological in nature, will probably be performed the following week). The maps should be collected throughout the season and the information should be graphed. It is amazing what a few seasons worth of historical and analytical graphs or bar charts will do to curb today’s mistakes tomorrow. Knowing, and seeing on graphs, that every March aphids visit the southernmost section of Greenhouse One will really go a long way toward planning a welcome back party for them. You have the time and place, so make it a surprise party (this year they can be surprised instead of you).

Okay, let’s move on, there’s more to cover.