附录setting是什么意思中文翻译
Plant Protection
Abstract
The cards on the upper surface were blue, says [John Howell]. In many cases, cards on the lower leaves were not covered as well. "If growers want to check out coverage in any kind of crop, they can get these cards from machinery dealers," says Howell. "It is a great way to determine what kind of spray coverage you are getting. We tested all these sprayers at 4 miles an hour and 2 miles an hour and we did it with the different types of sprayers."
[Headnote]
Increase yields by making sure your pumpkin and squash crops are adequately covered with a crop protectant.
OVER the years, disease pressure on pumpkins and winter squash, especially in the Northeast, has become more severe. More than 30 years ago, these crops were not typically
sprayed with fungicides or insecticides because it simply wasn't necessary. Disease and insect pressure wasn't that significant - back then.
Fast forward to about 15 years ago, and things were beginning to change. According to John Howell, retired extension vegetable specialist at the University of Massachusetts, as demand for these crops, especially pumpkins for Halloween, increased, so did production and the spread of plant disease, particularly black rot. The result was that spraying became a necessity.
"Growers didn't want to drive through their fields with a sprayer because they would squash a few squash, and pumpkins," says Howell. "We had to convince them that losing a few plants this way was better than losing much more to disease."
Sprayer Vs. Sprayer
According to Howell, most growers use high-pressure volume sprayers to apply insecticides and fungicides to row crops. Some use air blast sprayers and low-volume units.
From past research spraying insecticides and fungicides on pumpkins and squash, Howell learned that none of the sprayer types worked as well as they would have liked them to. Low-volume and air blast sprayers fell short in being able to successfully penetrate the canopy and achieve good leaf coverage.
Low-volume sprayers, says Howell, are typically used to spray herbicides directly on the soil, so applying product to plant leaves to prevent disease isn't the main goal. The air blast units, he learned, had difficulty getting coverage under the plant canopy. Of the three types, the high-pressure volume sprayers provided the best coverage to plant leaves.
"They all did a good job on the upper surfaces of the upper leaves," he explains. "However, you also want to be able to get the lower leaves that are lower in the canopy and the undersides of those leaves, as well. I think slowly more growers are becoming more aware of this issue with spray coverage."
During his research, Howell employed the use of water-sensitive cards. These yellow cards were clipped on the top upper leaves of plants and on leaves lower to the ground. Water w
as substituted for a crop protectant so researchers could walk through the fields after the plants were sprayed. Cards that got wet turned blue.
The cards on the upper surface were blue, says Howell. In many cases, cards on the lower leaves were not covered as well. "If growers want to check out coverage in any kind of crop, they can get these cards from machinery dealers," says Howell. "It is a great way to determine what kind of spray coverage you are getting. We tested all these sprayers at 4 miles an hour and 2 miles an hour and we did it with the different types of sprayers."
Using a high-pressure sprayer filled with water, these yellow watersensitive cards turned blue where water droplets hit them. The top card ? in each column is from an upper leaf, top surface. The second card is from an upper leaf, underside; the third card is a lower leaf, top surface; and the fourth (lowest) card is from cloverleaf, underside. It was difficult to achieve good coverage on the undersides of leaves.
Howell adds that spraying pumpkins and squash are particularly challenging, thanks to the
amount of foliage that needs to be covered. Researchers also are using water-sensitive cards to test the coverage of fungicides and insecticides on other crops, such as sweet corn, he says.
[Sidebar]
Use The Right Nozzle
JOHN Howell, a retired vegetable extension specialist at the University of Massachusetts, says growers should use a high-pressure sprayer on their pumpkin and squash plants and they should use a solid-cone nozzle. Most sprayers, he says, come with hollow-cone nozzles. "A solid cone has a narrower angle and tends to push the spray material further into the foliage," he explains.
He also tells growers to not exceed speeds of 2 miles per hour when spraying because it takes time to push the spray material down into the canopy. "If you are traveling too fast, you won't get good penetration of the foliage," he says. "You have to give the solution time to get down into the foliage as you pass over the crop."
Angling the nozzle also helps. On most  boom or high-pressure sprayers, growers can loosen the clamps on the boom, and angle it about 15 to 20 degrees forward as opposed to facing it straight down. By setting the nozzle on an angle, it tends to stir up the leaves a little bit and aids in the penetration of the canopy, says Howell.

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。