Thursday, August 16, 2018

The Corn Earworm



The corn earworm is one of the most destructive insect pests of corn in the world. But here in Hawaii it is not quite as destructive thanks to CTAHR (University of Hawaii College of Tropical Agriculture and Human Resources) plant breeders. Hawaii-bred corn varieties are more resistant to the earworm due to their thicker and tighter husks, thus limiting the number of larvae that can gain entry to the ear. This allows growers to simply cut off the tips of the ears to remove any damage that may have occurred.

Most of the eggs of the corn earworm are laid on the young silks soon after the silks have emerged. Young larvae crawl down the silk to feed on the kernels, soft cobs and the silk itself.  Luckily they also eat each other, keeping populations low.

Corn planted early in the year is not as seriously affected as is late corn because population densities increase as the season progresses. Early plantings will have minimal damage; later in the year one or two worms may appear in the tops of each ear of corn.

Control
To help control the pest, between plantings destroy the crop residue or haul it off to the compost bin. This eliminates places that would harbor the pest. Several natural enemies are present in Hawaii and, in general, they keep the corn earworm at tolerable levels. In most cases, control is simply a matter of cutting off damaged ends of corn at harvest.

For those gardeners who are plagued with the corn earworm, here are some chemical recommendations from the University of California IPM program:
  • Spinosad -  must be applied on silks within 3 days after first silks appear and at 3-day intervals until silks turn brown.
  • Bacillus thuringiensis (Bt) - may be dusted on silks every 3 days after 5 to 10% silk formation for partial control.
  • Applying a few drops of mineral oil with a medicine dropper to silks just inside each ear 3 to 5 days after silks first appear may be effective.

Monday, August 6, 2018

Bananas – A Fruit for All Reasons



There truly seems to be ample evidence that bananas are more than just a good source of potassium. Nutrients such as vitamin A, vitamin C, vitamin B6 and niacin, as well as the minerals phosphorous, calcium, magnesium and manganese are all present in bananas.

In addition, no fruit is higher in energy value except the avocado. This is because the banana has three natural sugars -sucrose, fructose and glucose which give a substantial boost of energy.

Other benefits of bananas are as follows:
  •         Help fight depression. They contain tryptophan, which converts into serotonin, a chemical known to make you relax and improve your mood. For this reason, bananas can also help sufferers of Seasonal Affective Disorder (SAD).
  •         High in iron. Bananas can stimulate the production of hemoglobin in  the blood and so helps in cases of anemia.
  •         Reduces the risk of high blood pressure and stroke. Bananas are extremely high in potassium yet low in salt. The US Food and Drug Administration allows the banana industry to make official claims for the fruit's ability to reduce the risk of blood pressure and stroke.  According to research in “The New England Journal of Medicine”, eating bananas as part of a regular diet can cut the risk of death by strokes by as much as 40%.
  •         Research has shown that the fruit can assist learning by making pupils more alert.
  •         Bananas have a natural antacid effect in the body so if you suffer from heartburn, eat a banana for soothing relief.
  •         Some people even rub mosquito bites with the inside of a banana skin to reduce swelling and irritation.
  •         Bananas can also help people who try to give up smoking. It seems the B vitamins, along with potassium and magnesium found in bananas help the body recover from the effects of nicotine withdrawal.

Monday, July 23, 2018

Hibiscus Mite

Bumpy, wart- like growths on hibiscus leaves

This unsightly growth is caused by the feeding of a tiny mite, invisible to the naked eye, called the hibiscus erineum mite.  It has been in the Hawaiian Islands since 1989 and is carried from place to place by wind, birds and insects.

The mite is difficult to eradicate, and even when it is gone, it will likely return.  Biological control is the best long-term solution.  Soon after the mite becomes established, a predatory mite will most likely move in and begin feeding of the erineum mite. 

Since the predatory mite will only reduce the pest population and not eliminate it, there will continue to be some damage. If not satisfied with biological control, using a chemical spray would be the next step:  1) prune to eliminate the worst damage, 2) spray with a registered miticide; wettable sulfur.  3) Apply 2-3 times, at weekly intervals, paying special attention to spraying the undersides of the leaves.  In addition to killing the mites, the spray will protect the new growth from further infestation so gradually the shrub will begin to recover. 

Unfortunately, a miticide application will also kill the predatory mites, so it is either biological control or chemical.  If you see tiny, fast moving mites on the leaves, these are the predatory mites. You may want to give them a chance before pesticide applications.

Research conducted at CTAHR’s Kahului Experimental Station (Maui) indicates that some hibiscus varieties are more susceptible to this mite than others.   The more susceptible varieties are:  Chinese Red, Herman Shierman, Orange Hibiscus, Nii Yellow and Kardinal.  Those varieties that show a lesser susceptibility to the mite are: Itsy Bitsy Peach, Monch, Zahm, Apple blossom, Apricot, Empire and Pink hibiscus.