无虫甜玉米
Fresh sweet corn is one of the best tastes of the summer. Put a little butter on an ear and chomp away!
The only thing that ruins this experience is when you open up the husks and find a worm inside.
We have tools to control earworms and borers. Insecticides such as carbaryl (Sevin) can be used, but most families prefer not to use toxic chemicals in their gardens. 有更安全的方法.
In the 1940s—before the age of synthetic insecticides—gardeners put a dab of mineral oil on the silks at the tips of the ears. 它工作. The worms suffocated on their trek from the silk tips down to the kernels.
Today, vegetable or corn oil is recommended. 更好的是，加一点 芽孢杆菌 苏云金 var. kurstaki (Btk)到石油. Btk is a natural bacterial insecticide that is widely used by organic growers (trade names include Dipel and Thuricide). Neem is another organic product that works well.
A formulation of 1 part Btk or Neem with 20 parts oil is recommended. 涂抹5滴(0.5 ml) from an eyedropper directly to the top of each ear.
时机至关重要. Spray when silks have reached their full length and began to wilt and turn brown (this is 5–6 days after 50% of the corn has begun to show silks). Earlier applications can interfere with pollination and lead to poorly filled ears. Later applications will lead to poor control, as the earworms will have escaped into the ears by then.
On a side note, did you know earworms are cannibalistic! 很酷的! That’s why you usually see only one worm at the tip of the ear. Let’s kill that merciless cannibal!
Commercial growers in the Midwest are finding earworm moths in their traps now. Moths are tan and often have a dark spot on each wing. The later we go in the season, the more likely the cobs will be visited by the earworm moths.
蛀虫也是个问题. They burrow in the stalk and tunnel into ears (photo). Look for shotholes or brown frass in the whorls at the time the tassels appear (photos below). If 15% of more of the plants show damage, spray inside the whorls with Btk, neem, or carbaryl. Spinosad is another organic option.
Written by Tom Kalb, 扩展 Horticulturist, North Dakota State University. 发表在NDSU庭院 & 花园报告，2014年8月11日. Photos were made available under Creative Commons licenses specified by the photographers: R.L. 羊角面包,Bugwood.org; Clemson University - USDA Cooperative 扩展 Slide Series, Bugwood.org; Eugene E. 纳尔逊Bugwood.org; Jan Samanek, State Phytosanitary Administration, Bugwood.org; Frank Peairs, Colorado State University, Bugwood.org.
来源:
正义前锋,R. 和P. 韦斯特盖特. 2005. Organic insect management in sweet corn. 可持续农业研究 & 教育.
