Mixing Herbicides and Insecticides: A Comedy of Errors
Ah, the age-old battle of the bugs and the weeds—like a tragicomedy unfolding in the agricultural world where every spray counts! Today, let’s take a closer look at the article that dives deep into the riveting realm of root products versus contact insecticides. Spoiler alert: it’s as thrilling as watching paint dry, but with bugs!
The Quality of Spraying: A Necessary Evil
So, if you thought you could just fling your mixing concoction around carelessly, think again! Our dear 2021 essays on prosulfocarb—which sounds like a character from a sci-fi flick—tell us that air injection nozzles are your best friend in this chemical opera. Why, you ask? Because they reduce drift and limit the volatilization of these products to the ground. A bit of a stretch, but we all want our sprays staying put, right? Remember, they’re mandatory for prosulfocarb. You wouldn’t want to be the one to accidentally fling that weed-killer into your neighbor’s garden, would you?
And then there are the pyrethroids—those little contact-loving divas—where the quality of spraying truly influences their effectiveness. They’re like a picky eater at a buffet; if you don’t serve them right, they’ll simply refuse to do their job. A few tests conducted with the ITB in 2022 (that stands for “Incredibly Tricky Business” in my book) showed that at 50 l/ha and 80 l/ha, only the classic slot reference nozzle properly delivered the goods. At 150 l/ha, well, let’s just say the air injection nozzles were invited to the party. However, that 90% approved nozzle? It could be a tad too large to do the contact dance, which isn’t a surprise for anyone who’s ever tried to tango with an elephant.
Different Technical Positions: Like Different Sides of a Coin
Now, let’s not forget our dear friend, Mr. Timing. Pyrethroids are like the overenthusiastic party-goer who shows up early—totally useless if applied preventively. Timing is everything! You’ve got to wait until you see those aphids making themselves at home in your crop. Meanwhile, root herbicides are like the strict teacher who enforces a limit stage of application. In the case of prosulfocarb, we’re talking about the 3-leaf stage of the cereal. Moist soil? Yes please! The more moisture, the merrier! The stars rarely align for both application timings, and maybe—just maybe—this explains why mixing them correctly feels a bit like herding cats.
What to Do in Case of Mixing? The Drama Continues
If fate has determined that both herbicide and insecticide applications are necessary, the best approach is to apply the mixture at a minimum of 150 l/ha with air injection nozzles approved at 66% or 75%. Think of it as balancing on a tightrope while juggling—easy peasy, right? But hey, **separating applications** is usually the best course of action. This way, you can safely employ a nozzle approved at 90% for prosulfocarb—because reducing the safety distance to local residents to 10 meters is the dream. Just steer clear of that nozzle when it comes to contact insecticides, or you might as well hand out coupons for pest survival to your neighbors.
Author: Benjamin Perriot (Arvalis).
If the root products require moist soil for the uniform distribution of the product, they are not influenced by the volume of spray mixture or the type of nozzle employed. In stark contrast, contact products like pyrethroids, which specifically target fall aphids, are highly sensitive to these variables.
The quality of spraying must be taken into account for insecticides
The 2021 essays on prosulfocarbe distinctly demonstrated that air injection nozzles are effective regardless of the spray volume when using root herbicides. These nozzles are recommended primarily to reduce drift and minimize the volatilization of these crucial products into the atmosphere. It is important to note that air injection nozzles are mandated for the application of prosulfocarb.
As for the pyrethroid insecticides, which primarily operate through direct contact with pests, there exists limited literature on best practices. However, tests conducted by ITB in 2022 on contact herbicides reveal that the quality of spraying significantly impacts their efficacy.
By evaluating three spray mixture volumes alongside four types of nozzles (one traditional slot nozzle and three varieties of air injection nozzles), clear patterns emerged concerning the effectiveness of these factors. At volumes of 50 l/ha and 80 l/ha, only the traditional slot nozzle achieved satisfactory results, whereas at 150 l/ha, compatible air injection nozzles showed a 66% and 75% reduction in drift. Conversely, the nozzle rated for 90% reduction yields droplets that are excessively large for a contact herbicide.
Different technical positions
It is crucial to understand that pyrethroids deliver little to no effectiveness if applied preventively. Their application must coincide with the active observation of aphids within the fields.
Root herbicides, such as prosulfocarb, are constrained by a limit stage of application—specifically, the 3-leaf stage of the cereal—and thrive under moist soil conditions to enhance their efficiency.
Given that the timing for herbicide application rarely lines up with the optimal timing for insecticide treatment, it becomes evident that achieving a mix of both products can be quite challenging. This is particularly true in managing two distinct targets: grass weeds on one hand and aphids or leafhoppers on the other.
What to do in case of mixing?
Should pest pressure justify the use of an insecticide during herbicide application, the mixture must be administered at a minimum rate of 150 l/ha, utilizing air injection nozzles rated for 66% or 75% efficacy to enhance the effectiveness of both treatments.
However, in most circumstances, it is advisable to keep the applications separate. This allows for the use of a nozzle approved at 90% for prosulfocarb, which reduces the mandatory safety distance from neighboring residents to 10 meters instead of the usual 20 meters. Nevertheless, care should be taken to avoid employing such a nozzle for contact insecticides.
Author: Benjamin Perriot (Arvalis).
