Saturday, February 2, 2019

Bugs - the Good, the Bad and the Ugly



Not all bugs in the garden are bad. 
Some bugs are beneficial. such as parasites and predators. The are looking for pests to consume. Two well-known good guys are preying mantis and lady bird beetles; spiders are also good predators.  Biological control can work very well. As an example, in California when certain species of whitefly came into a new area, both citrus  and some vegetable crops were damaged or completely destroyed. Yet within a number of years, their natural enemies were established, and for the most part, the pest became inconsequential.  Pollinating insect can also be categorized as beneficial.

Some bugs may be found on a plant, but are not feeding and therefore cause no damage. The bug may simply be resting or perhaps searching for nectar or another source of food.                                                                                                   
               
Some insects of course are known pests, but cause little damage. A bite may be taken from a leaf here and there,  or a little juice sucked from a stem, but overall, the plant is not harmed. 
On the other hand, some bugs do inflict damage, but it is only cosmetic. That is, the leaves or fruit may be scared or misshapen, but there is no real loss of yield.  In many cases, cosmetic damage should be tolerated. This type of damage on citrus fruit is caused by thrips and does not affect the internal quality.    
Above Photos: University of California IPM Program

And finally, if there is an infestation of an insect pest which will cause yields to be significantly lowered, the gardener will have to decide whether to wait a bit and see if biological control will work. If a parasite or predator can control the pest population, no intervention is needed. Yet if spraying is the choice, consider first a bio-rational pesticide, such as soap, oil, Bt or sulfur. These are less injurious to the environment, and may not harm the predator or parasite populations. 

And, the Ugly
Colorized image of a flower beetle
Arizona State University




Wednesday, December 26, 2018

Poinsettias

This is the time of year many people have poinsettias. What to do with them after the holidays?

Care 
  • Poinsettia plants prefer indirect light, six hours daily is ideal.
    • Poinsettias require daytime temperatures of 60 to 70°F and night time temperatures around 55°F for best growth; high temperatures will shorten the life of the plant.

    • Standing water can be harmful for the plant. Remove any wrappings from around the pot or punch holes in the foil so water can drain into a saucer; discard excess water.  
    • In some climate zones poinsettias can be planted outdoors.
    Yet, some are concerned because they think the plants are poisonous. Are poinsettias poisonous? No, this myth has been around since the early 1900’s. The American Society of Florists has been trying to dispel the myth for a long time. They say that no other commercial plant has been tested for toxicity more than the poinsettia.

    According to the American Medical Association’s Handbook of Poisonous and Injurious Plants, ingestion of the poinsettia plant has been found to produce no ill effects except an occasional case of vomiting. According to the POISINDEX information source, a child who weighs 50 lbs. would have to consume over 500 leaves before he reaches a potentially toxic level. Since the taste of poinsettia leaves is reportedly unpleasant, it is unlikely that a child or animal who attempts to eat or chew the leaves, will continue to do so after the first taste. Some people, however, can develop a skin and eye irritation from contact with the milky sap of the plant.



    Saturday, December 1, 2018

    Citrus - Ripe or Not

     In tropical regions of the world, some gardeners patiently wait for their citrus fruit, such as tangerines, to turn orange before picking them.  When using color as an indicator for ripeness, the fruit can easily pass its prime, which is characterized by dry fruit segments. 

    Coloration can be an indicator for ripeness in temperate and subtropical climates like California. But in the tropics, color is not a good guide for harvesting. Large temperature differences, such as 85 F. in the day and 45 F. at night, is the condition which produces the orange coloration.  This is also true in other fruit such as apples. 
    In contract, temperatures in the tropics do not significantly vary; thus fruit tends to stay at least partially green.
     
    If you know the variety of the fruit, you can find out the harvest period. If you don’t know the variety, then when the fruit first begins to show color, pick one and taste it. If it’s not ripe, or not sweet enough, wait a week or two and pick another. Fruit will sweeten when left on the tree. Eventually you’ll discover the right time and know the approximate picking schedule for next year. 

    Once citrus fruit is picked, it will not continue to ripen and become sweeter unlike other fruit such as the banana.