Showing posts with label mites and spiders. Show all posts
Showing posts with label mites and spiders. Show all posts

Monday, May 13, 2013

Stunted Pepper Plants

The  pepper plants are stunted, and the leaves are crinkled, what’s the problem?

There are a number of factors that contribute to stunting: nematodes (check for knotted/galled roots), under irrigation, over irrigation and lack of fertilizer.  The crinkled leaves, however, give a clue in diagnosing the problem. The mosaic virus complex is a common disease of peppers causing green and yellow mottling, crinkling and distortion of the leaves, and stunting of the plant. There is no control for the virus itself. Since viruses are systemic, removing infected leaves or pruning out infected limbs, in the case of a tree, would not be a correct control method.

Insects such as aphids, transmit many viruses, therefore, controlling these pests would help. Removing the surrounding weeds is important since they may harbor the virus, too. The use of a reflective mulch to cover the soil around the plants may be effective in repelling aphids and thus help to limit the mosaic virus.

Lastly, it always helps to plant the right variety.  The University of Hawai`i recommends for bell peppers the following varieties: keystone resistant giant, summer sweet 760, grande rio, tambell ll, yolo wonder, California wonder, emerald giant, titan, midway, bell boy hybrid and banana large yellow. The hot peppers recommended are Anaheim chili, Hawaiian chili, jalapeno, long red cayenne and Hungarian. Check with your local University Cooperative Extension office for varieties in your area.

Monday, February 20, 2012

Controlling Pests on Houseplants

 Houseplants are susceptible to many unsightly insect and mite pests. Some pests cause extensive damage, while others are merely a nuisance.
Here are some control measures:
·        A healthy plant is much more resistant to insect and mite injuries.  Keep house plants well fertilized and adequately watered. Keeping the soil excessively moist favors the development of root rot along with an increase of nuisance pests like the fungus gnat.  When soils are kept too dry, plants are prone to mite problems.
·        Many infestations are brought home with a newly acquired plant. Carefully inspect all plants that are taken home. 
·        Syringing plants - many household plant pests can be controlled, at least in part, by washing the plant periodically with a vigorous jet of water. This is particularly effective for spider mites and aphids, which are readily dislodged.
·        Vacuum – if you have whitefly problems, the regular use of a small, hand-held vacuum can assist in controlling this pest.  Careful not to vacuum up the plant!
·        Sanitation - Seriously infested plants are often best discarded. They can serve as a source for infesting other plants.
·        Alcohol – use  Q-Tips dipped in alcohol to wipe small infestations from the plant.
·        Pyrethrins, synthetic pyrethrins (known as pyrethroids), insecticidal soaps, horticultural oils, Neem (derived from seed extracts of the neem plant) and Neem oil can all help in controlling most houseplant pests. Some insecticides, especially the oils, can burn some of the more delicate houseplants.  When in doubt, spray one or two leaves and wait 3-4 days before spraying the whole plant. 
·        There are also systemic insecticides which are absorbed into the plant. As the insect or mite feeds on the plant, they will die.  Look for an insecticide with the active ingredient, Imidacloprid.
                                                                        Mealybug on Palm

Safety Issues:                                    
Only use pesticides that are specifically labeled for use on houseplants. Most yard and garden pesticides do not allow this use.  If possible, take the plant outdoors before spraying to minimize pesticide exposure within the home. When using aerosol sprays, do not apply closer than 18 inches to the plant or injury may occur from the spray.

Friday, January 13, 2012

Spiders: Friend or Foe?

Spiders are beneficial creatures and are the best bio-control agents known.  They should be tolerated as much as possible since they feed on large quantities of insects such as aphids, ants, thrips and termites. 

Most people would rather not have a house full of cobwebs. But spiders capture and consume many household pests including flies and once in a while, a centipede. Spiders are actually classified as arachnids and not insects; spiders have eight legs, insects have six.
There are over 3,000 species of spiders in the U.S., and only a small number of these are dangerous to people; very few are equipped with mouth parts that can actually pierce the human skin. 

For people who won’t tolerate spiders, here’s what to do.
·        The easiest and safest way to rid your house of spiders and their webs is to vacuum rather than spray.  The dust inside the vacuum bags will quickly suffocate any spiders you catch. If you’re willing to share the house with a few spiders, you can periodically vacuum up the webs that are eyesores and leave the spiders to continue their job of controlling the household pests.
·        If you can catch a spider in a jar, take and release him outside where he can continue working.  You might try caulking cracks and installing screens to prevents more spiders from coming inside.

Friday, December 16, 2011

Crab Spiders

 Each fall local gardens are invaded by crab spiders, also known as spiny-backed spiders.  There are two species of crab spiders on the Big Island of Hawaii, both are shaped like tiny crabs approximately ½ inch across. One is white with black spots and 6 red spines. The more common one also has spines, although shorter, with two distinct white spots on its speckled yellow-brown back.  At least in Hilo, Hawaii, crab spider populations increase in the fall and decline in the late spring.

These spiders are different from other spiders in their web building techniques. Their webs are interconnected, building condominiums right outside your door, under the eaves, between the shrubs and in the trees.  They seem to be spun everywhere, but the spiders are not a nuisance indoors. 

People, especially farm worker, have been bitten when the spider falls on them or gets trapped within their clothing.  Females lay eggs away from their webs, on the leaves of trees and elsewhere. The egg masses look like a flat patch of fluorescent green cotton candy which turns yellow when the eggs hatch.  Disposing of this egg mass will, of course, help to reduce the spider population.

Spiders, including the crab spiders, are some of the best bio-control agents known, because they feed on large quantities of insects such as aphids, ants, thrips and termites. They should be tolerated as much as possible. But, people do have their limits.  A soap and/or oil solution will kill them. In addition, many  household, aerosol insecticides will do a good job of killing the spiders. Before using, read the label for precautions and application sites. Note: application to plants may cause severe burning.

Monday, November 7, 2011

Lychee mite

The rust like appearance on the leaves of the lychee tree is a very common occurrence.  It is not a disease but rather is caused by a tiny mite (Erinose mite) about 1/200 of an inch long. The foliage has been described as curled, distorted and galled, with a velvety brown to brownish-red appearance on the underside. These mites attack new leaves at the onset of growth flushes. 
Mites infesting young trees may cause a stunting of the tree.  At this stage, when trees are manageable, infested leaves can be removed and discarded. This will help reduce the mite population and allow the young trees to grow more vigorously. Generally as a tree becomes larger, removing infested leaves is difficult. However, mites seldom kill a tree. It’s probable that the tree will continue to be plagued with mites, but you should be able to harvest a normal crop of fruit.

Friday, October 7, 2011

Hibiscus Mite

Bumpy, wart- like growths all over 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 get rid of, 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 always be some damage.  If you do not want to tolerate any damage, then you will have to spray.  Prune first to eliminate the worst damage, then spray with a registered miticide (wettable sulfur has worked).  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. 
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.