Monday, May 27, 2013

What is Calamondin?


For many years the calamondin, or calamansi was grouped in the Citrus genus. It is now thought to be a hybrid, a cross between a tangerine (genus Citrus) and a kumquat (genus Fortunella) and has its own genus, Citrofortunella.  This fruit originated from China and has been described in Chinese literature as early as 1178. 

The Calamondin is a small tree, 7 to 25 ft. in height. The orange colored fruit are round to oblate and up to 1 ¾ inches wide. The peel of the fruit is sweet and edible while the juice is quite acidic.

Calamondins can be used to flavor anything where lemons and limes would be used and are often served with iced tea and seafood.  They were common in Florida before limes became plentiful.  Calamondins can also be preserved whole in sugar syrup, or made into sweet pickles or marmalade; a favorite is a calamondin-papaya marmalade.

 Calamondins haves been reported to promote hair growth when the juice is applied to the scalp after shampooing. Rubbing calamondin juice on insect bites removes the itching and irritation. 

In regards to horticultural care, calamondins should be treated as other citrus.

Monday, May 20, 2013

The Fungus Gnat - A Nuisance Pest

Adult fungus gnats are primarily a nuisance pest, although some damage can be done to plants due to larval feeding on root hairs.   This type of damage can be serious in greenhouses and nurseries.

Fungus gnats thrive under moist conditions, particularly where there is an abundance of decaying vegetation, algae, and fungi. They infest the soil and container media, specifically those rich in organic matter. Fungus gnats do not bite people or animals and are not known to carry human pathogens. They do have a beneficial role as decomposers helping to convert dead vegetation into nutrients for plant growth.

The adults are dark in color and similar in appearance to mosquitoes. They are about 1/16 to 1/8-inch long, although they can be larger. The gnats are relatively weak fliers and are usually not found flying around indoors.

Females lay tiny eggs in moist organic debris or potting soil.  The immature, legless larvae have a white to clear body with a shiny-black head and when fully grown are about 1/4 inch long. The larvae live in the soil and feed on organic mulch, leaf mold, grass clippings, compost, root hairs, and fungi.

Cultural and physical control includes reducing moisture as much as possible, eliminating any plumbing or irrigation system leaks and providing good drainage. Moist grass clippings, other organic mulches and composts are favorite breeding spots. The use of partially composted matter in potting mix will encourage the infestation of gnats.

Insecticides are used in commercial plant production but are seldom warranted to control fungus gnats around the home.  Bacillus thuringiensis subspecies israelensis (Bti) applied to the soil or potting media is a safe product for the control of fungus gnats. Repeated applications are needed for long-term control. Note: This particular Bt product is different from the one used to control caterpillars. Bt labeled for caterpillars is not effective against fly larvae. Insect growth regulators (kinoprene, cyromazine) applied to the potting mix can also be effective.

Pyrethrins or a pyrethroid (bifenthrin, permethrin) are an option to provide temporary, fast-acting control. Pyrethrins have low toxicity to people and pets. When spraying houseplants, it is best to move the plants outdoors for treatment and wait a day or so before bringing them back inside.

Biological Control - Predators, such as some beetles, mites and nematodes will help to control fly larvae outdoors.  

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, May 6, 2013


Mamaki (Pipturus albidus)  is a Hawaiian endemic plant occurring on all the main Hawaiian Islands except Ni'ihau and Kaho'olawe. It grows in moist to wet forests at elevations ranging from close to sea level to 6,000 feet. It is generally not suited for hot, dry coastal settings, but will grow well in urban landscapes with some shading. 
It will also do well planted in containers in part shade. The red-veined varieties appear to tolerate full sun better than green-leaved varieties. 

Mamaki is a highly variable plant. The leaves are dark-green on the 
top and white to gray underneath; some varieties have reddish veins. It can be considered a shrub or a small tree ranging in height from 6 to 20 feet tall.The mature plant recovers after pruning if no more than one-third is removed.

Plants are usually propagated from seed. The fruit can be ripened in a plastic bag to soften the pulp. Seeds are then removed from the pulp by rubbing the fruits in a strainer under running water. The viable seeds will sink and the fruit pulp and other debris can be poured off. Seeds then need to be dried on a paper towel and stored. Once planted, seedlings will thrive in a well-draining soil in a semi-shaded to shaded location.  In addition they can also be propagated from cuttings.   

In Hawaii dried or fresh mamaki leaves are used to make a tea often drunk by those feeling lethargic. The tea is also reported to help with many internal disorders such as for the stomach, colon, bladder, liver, and bowels.  The fruit is eaten as a laxative and also for stomach, colon and digestive problems. Infused leaves can be used in treatment for high blood pressure, high cholesterol, liver problems, and bladder problems. In some people mamaki can cause mild agitation or insomnia.

Mamaki is the primary food source for caterpillars of the native Kamehameha butterfly. Planting this shrub in the garden will provide a healthy, invigorating tea for the gardener and food for the butterfly.

Photos by Forest and Kim Starr