Archive for parasites

Rose Galls by George Giltner, Louisiana Master Gardener

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Rose Galls by George Giltner, Louisiana Master Gardener

If you cut inside of plant galls, chances are that you will discover an insect larva.  The bugs have found a unique way to provide a protective habitat and food for the developing larvae.  The exact mechanisms for gall formation are variable, but plant growth chemicals released by  larval salivary secretions cause these distortions.  Some galls are smooth while others are spikes, or fibrous like the mossy rose gall.  Other solid galls are produced by mites, nematodes, bacteria, fungi, and viruses.

Rose gall, Photo by Ohio State Extension

The mossy rose gall is the common golf ball sized growth caused by the 0.2 inch cynipid wasp (Diplolepis rosae).   Chances are that you will never see these small wasps, but you will notice the galls.  Each one of these growths is capable of producing about 30 additional wasps which will be seeking other Moss Roses (Rosa centifolia mucosa), R. rubiginosa,  R.dumalis, and R. rubifolia.  Therefore it is wise to prune off these unsightly growths before they mature.

Most insecticides are not effective in controlling these wasps.  Since the typical infection is usually one to two galls, it is much easier to just prune and destroy the gall.  Make a slightly angled cut about ¼ inch above a bud in pruning.

Birds, especially woodpeckers enjoy feeding on the emerging wasps from the Mossy Rose gall which occurs from May to August.  Mice and other small mammals recover the larvae or pupae from the galls.  Also parasitoid insects are natural predators that attack the galls.

An interesting fact is that nearly all of the cynipid wasps produce asexually.  A bacterium, Wolbackia, causes the infected females to produce only female progeny.  When an antibiotic are used to kill the bacteria, females then produce normal quantities of both males and females.

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Honey Bee Enemy #1: Varroa Mites

By George Giltner, Master Gardener

LSUAC4C72-80px[1]MasGarTM5x7_w85[1] A Blog from the LSU AgCenter & Beauregard Master Gardeners

                      Honey bees pollinate about 1/3 of the human diet, directly or indirectly to apples, blueberries, and 130 other crops in the United States.  For fruit and nut crops, the degree of pollination dictates the maximum yield and profitability of these crops.  This is why bee pollination services are reported at $9 billion plus within the United States alone.

Valuable bee populations have risen and fallen within the past decade due to numerous causes.  Some report that the honey bee’s worst enemy is man with improper use of insecticides.  However I disagree. We propagate bees, promote their good genes, aid their health against natural diseases, and supply them with abundant foraging acreage in a mutual beneficial relationship.  Enemy # 1 is debatable, but Varroa destructor, a mite (below arrow above) rate very high on the list.  The worst enemy is the one in a beekeeper’s hive.

Varroa mites actually originated in Asia.  There they did little harm to the eastern honey bees.  But when American honey bees were brought to Asia, the devastating damage to hives became evident.  Then over the past 100 years, these mites have spread worldwide.

5 varroa mites

A Varroa mite (under blue arrow) attacking a juvenile honey bee

The adult mites are reddish brown, round, and range from one to two millimeters in diameter.  Varroa go between the bee segments, puncture the soft tissue, and feed on bee hemolymph through the puncture.  The mites are passed from bee to bee in the hive.  Also they are transported to other hives when bees drift into other hives, when healthy bees rob weaker hives, and when beekeepers put hives in new locations.

When the mites reproduce, they enter the brood cells of larval bees that are about to be capped.  The mites feed on the bee larvae, lay eggs that soon hatch, and both continue to feed on the bee larvae.  The result of this feeding is damage or death to the developing bee.  It is safe to assume that hundreds of thousands of bee hives have been destroyed, causing billions of dollars of economic loss.

It sounds hopeless, but beekeepers can take countermeasures.  Sticky traps underneath a screen bottom tray can capture the varroa mites as they frequently fall off the bees.  Placing colonies in full sun modestly reduce varroa numbers.  Fogging mineral oil and dusting the bees with powdered sugar have not been proven to be effective to this date.

The most significant advancement toward control has been through genetic breeding programs.  Favored genes are associated with bee behavior.  One behavior is for the bees to groom themselves and other bees in the brood.  Therefore mites are knocked off the bees lowering the mites in the bee colony.  Another behavior is hygienic bees that can detect problems in the developing brood.  They uncapped the infected larvae and remove it from the hive.  This hygienic behavior is called ‘varroa sensitive hygiene’ or simply ‘VSH’.  Bees with these genetic traits can be purchased from specific bee suppliers.

Contact Keith Hawkins (337-463-7006) at the LSU Agcenter or the Southwest Beekeeper’s Association for additional information.

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Open Bee Hive for Inspection…..Nov 2012

by Jimmy Earl Cooley, beekeeper & Master Gardener

LSUAC4C72-80px[1] A Blog from the LSU AgCenter, Beauregard Parish, LA

I have been feeding sugar water for two months in hopes of giving necessary food to tempt bees to fill the two empty frames in my top, of two, brood boxes with sugar.  I opened the hive in Nov 23rd and found it amazingly clean and free of hive beetles and all bees docile and cooperative. Although the two frames were still completely empty with no activity, although they were consuming a quart bottle of sugar water every few days.  Must be using to support the hive or other bees and yellow jackets stealing water.  I rotated the entrance board to reduce the entrance hole from approx. 3inch to 1 inch for winter and placed spacers between inner cover and top cover to allow for ventilation during winter.  I removed several frames from top brood box and looked down to bottom brood box and everything looked good and clean and full of bees.  Noticed on the side of a frame from top brood box, what appeared to be a queen cell or maybe several together, with openings on top, as if queens may have hatched out.  I did not pull any lower or other frames from top box to search for queen. So looks like winter is progressing without incident or problems.  Plan to open hive again for quick inspection in Dec.  Comments appreciated.   Jimmy Earl Cooley 11-24-2012

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