Friday, January 13, 2017

Replanted Vegetables Dying

Why do vegetables continue to die no matter how many times I replant? There are soil borne plant diseases that can survive in the garden, either on plant debris or in the ground itself. Once infected, the soil can remain so year after year. Some of these diseases have a wide host range, while others attack either one particular species only or may attack members within a particular plant family. Planting the same crop year after year in the same location will allow for the pathogen to build up to high levels. 

One of the best control measures for the soil borne diseases is crop rotation. This will allow time for the plant debris to decay and the associated pathogens to die out. The time required for this to happen varies. Some diseases survive up to 10 years or more, but most recommendations suggest periods of one to four years before returning to the original crop.

Keep in mind that a fungus that attacks, for example, the roots of lettuce will usually not attack beans. If tomatoes are being grown one year, do not come back and plant tomatoes again, or potatoes, peppers and eggplant for that matter – they are all in the same family.  This is a good practice even if no diseases are detected.

Another important step in disease prevention is to take advantage of any resistant varieties that may be available. For vegetables, check with seed catalogs to see if they have varieties that are resistant to a specific disease. The same is true with fruit trees since certain varieties are more resistant to diseases.   

Note: resistant (or tolerant) does not mean immune. A resistant plant will be less affected by the disease and show fewer symptoms. A plant that is immune will not be affected by the disease. Unfortunately, some resistant varieties may lack certain desirable characteristics in the plant such as flavor or high production. If you can find resistant varieties, the battle against disease is half over.

Ask the Garden Guy, Science Based Answers to Garden Questions, is an excellent resource book for gardeners. Some popular topics include Slugs and Snails, Organic Pesticides, Why Vegetable Seeds Do Not Germinate, What’s So Hot about Manure? Mushrooms in the Lawn.  Purchase by clicking on the image of the book above. 

Saturday, December 31, 2016

Gold Dust Day Gecko

The Gold Dust Day Gecko, a native to Madagascar, sometimes referred to as the Madagascar Day Gecko, does well in a tropical climate. Unlike most geckos, it is a diurnal animal, active during the day. They are territorial animals; males are especially aggressive towards other males.

These geckos are very colorful, usually bright green or a yellowish green. Halfway down their backs, they have three red teardrop markings. A blue shade is present around the eyes with bright gold markings on the back and neck. They feed on various insects and other invertebrates and are capable of eating other smaller lizards. They also eat soft, sweet fruit as well as pollen and nectar from flowers.  But they don’t bite humans.

Although these geckos will come into the house, probably looking for food, they are an arboreal species, spending most of their time in trees. If exclusion is desired, treat them as you would mice, rats and cockroaches; make sure to screen all windows, doors, ventilation passages and any small openings into the house.

Another species of gecko is the House Gecko, residing with humans in homes rather than in the wilderness. Being aggressive, this pale brown gecko drives other species away from the house. They are primarily nocturnal.

There are over 900 species of geckos worldwide, but only seven or eight reside in Hawai`i. Geckos are the only lizards who are able to make sounds, other than hissing.  Feeding on cockroaches, mosquitoes, ants, termites and moths, geckos are beneficial to home owners.

It has been thought that geckos are able to run up and down walls and ceilings due to tiny suction cups on their toe pads. However, recently scientists found that geckos have a network of tiny hairs and pads on their feet. With millions of hairs on each foot, the combined attraction of the weak electrical forces allow the gecko to stick to virtually any surface, even polished glass.

Tuesday, December 20, 2016

Citrus Skirt Pruning

Occasionally citrus trees have been pruned up off the ground. Some have asked, "What is the reason for this?"

Skirt pruning of citrus has been around for a long time in those countries surrounding the Mediterranean Sea. The skirt of the tree includes those branches which hang down and touch the ground or are near to the ground.  In Italy, the skirts are pruned as high as the goats can reach.

In the United States, California in particular, skirt pruning done with clippers or a pruning saw, not goats, is a recent development and mainly came about as a means of controlling snails in the orchard.  By skirt pruning, usually 18 – 24 inches, snails as well as ants are denied easy access into the tree. Then the trunk is the only route.  Farmers can concentrate their pest control efforts on a small area, the trunk, rather than spraying the whole tree with pesticides. In the case of snails, copper foil is often banded around the trunk; snails will not cross the copper band. For ants a sticky material is sometimes applied.

Skirt pruning will also help control brown rot disease of citrus fruit. Since low hanging fruit is eliminated, the overall fruit quality will improve.