Controlling Insects with Neem

 The neem tree (Azadirachta indica) is a fast growing shade tree native to Southeast Asia and India. Compounds (Azadirachtin) extracted from the seed have been found to possess pesticidal qualities; the greatest concentrations of these substances are found in the seed.

Also extracted from the seed kernel is the oil. Neem oil, like other horticultural oils, works by suffocating the insect, coating its body and blocking the breathing openings. Products are available which contain neem oil alone or with azadirachtin.  In tests involving the control of aphids, products containing both had a greater efficacy than either ingredient alone.  Neem oil can also prevent the germination of some fungal spores such as powdery mildew. 

Azadirachin, the active ingredient in many neem products, actually consists of more than 25 closely related compounds.  They work in several ways. 1.  as a feeding deterrent against a number of insect pests. 2. to disrupt the molting process so the immature larvae do not develop into adults.  3. some insect larvae are killed by direct contact with the spray,  4.  adult insects are normally not killed but mating may be disrupted and 5. Azadirachtin also has a repellent effect on certain insects and mites.         

Insect pests affected by azadirachtin include aphids, beetles, caterpillars, lace bugs, leafhoppers, leafminers, mealybugs, psyllids, thrips and whiteflies.  Generally, neem will have less of a detrimental effect on beneficial insects (parasites/predators) compared to the broad spectrum pesticides.

Multiple applications of neem are generally recommended. Frequent spraying is more effective because neem does not persist on plant surfaces. Like other botanical insecticides, it is quickly broken down by sunlight and washed away by rain. For smaller plants, neem seems to work well as a soil drench; the product is absorbed by the roots and translocated systemically throughout the plant.

Another product sold as a fertilizer is neem cakes. They are the residual seed meal remaining after extraction of oil from seeds. 

Bolting in Vegetables

Bolting is the process of premature flower formation in response to high temperatures, as well as drought and starvation.  This unwelcome occurrence in leafy plants such as broccoli, cabbage, lettuce, and spinach,  takes the plant out of its leaf producing mode and switches over to flower and seed production.

Many vegetables are divided into two groups: cool season and warm season vegetables. Although in Hawaii seasons may vary little in temperature and many vegetables can be grown year around, some will do better when planted within the given time frame. 

Broccoli and lettuce are cool season vegetables. As long as the temperatures remain cool, the lettuce will continue to produce tender leaves, and the broccoli flower buds will remain closed. Generally lettuce and broccoli are planted from September through March/April.  During the hot summer months plants can bolt.  At higher elevations, cool season vegetables such as lettuce, beets, broccoli, cauliflower, chard, kale, peas, turnips and mustard, may be successful planted in late spring and summer.   

Warm season vegetables include tomatoes, cucumbers, melons, squash, peppers, corn and eggplant.

Propagation of Blueberries

Blueberries are propagated from either softwood or hardwood cuttings. 

Hardwood cuttings  are collected in late January or February, after sufficient chilling has occurred.  1. Select healthy material. 2. Avoid propagating from plants that have odd-looking or stunted foliage. 3. Collect shoots from the previous summer, 12 to 36 inches in length.  4. Divide these shoots into pieces 5 to 6 inches long, removing any flower buds. 5. Place cuttings in a propagation bed at a depth of one-half to two-thirds of their length. Keep moist.

Softwood cuttings are taken in late spring from the current season's growth, 4 to 5 inches long.  Collect these cuttings when the stems have developed woody tissue but are still somewhat flexible. Remove all leaves with the exception of two or three terminal leaves.  Place cuttings in the propagation bed, under mist at a depth of one-half to two-thirds of their length.

Rooted cuttings are eventually transplanted into pots and held for about one year.   During the time of rooting, keep beds moist while being aware not to over water.

A greenhouse is not necessary, but some type of propagation bed/chamber, under 40 to 70 percent shade with a mist system is recommended; an area as small as 3x3x3 can be used.

The mist system should keep the media uniformly moist but not soggy.  An intermittent-mist system with frequent, short misting intervals is recommended in order to keep the humidity near 100 percent.  However, keeping the cuttings at this constant moisture also creates an ideal environment for pathogenic fungi to grow. Thus cleanliness is very important; use new or sterilized planting mix and pots, keeping them raised off the ground.

Potting media containing various mixtures of coarse sand, ground pine bark, perlite, sawdust, and peat moss have proven satisfactory.  One such recipe is a mixtures of coarse sand, ground pine bark, and peat moss (1:1:1) and perlite and peat moss (1:1)