What is the difference between systemic and non-systemic pesticides?

Wormwood or absinthe 

Wormwood (Artemisia absinthium) is a small perennial shrub, with a bushy growth habit, of an ashy-green color, which can reach 1 m in height. It is native to Europe but also grows in Asia and Africa. Wormwood belongs to the Compositae family and to the genus Artemisia, which is composed of a large number of small herbaceous plants of which some 280 species are found in the northern hemisphere; they are very widespread in arid zones. The flowering generally occurs between July and August. The fruits are achenes. The plant is also known under various other names among which: Holy grass, worm grass, virgin grass. Absinthe is composed of a number of chemicals including malic acids, succinic acids, ascorbic acid, flavonoids, tannins and resin. The essential oil is formed mainly from thujone and thujal. Thujone, causes strong excitations of the nervous system, followed by a brief period of unconsciousness and generalized convulsion. Absinthe has been used since antiquity for the treatment of digestive disorders. The active parts of the plant are all very bitter. They are used in internal treatment either pure or in mixtures, to stimulate the appetite, the secretion of the digestive juice and bile, against intestinal colic as well as against intestinal parasites. In Morocco, absinthe is used to flavor tea, especially in the winter period.

Epidapho-climatic requirements

Wormwood is a xerophytic plant. It grows in regions with low rainfall. It can be cultivated in arid, dry areas with temperatures ranging from one extreme to the other. Its plantation requires sunny places. Absinthe is not demanding in terms of soil; it grows just about everywhere on rocky, dry and arid land. It also thrives on clayey calcareous soils. It is even indicated to develop poor land that is unsuitable for other crops. However, observation shows a predilection for saline sandy soils.

Varieties, seeding and tillage

Multiplication is done in two ways:

(1) The sexual way (the sowing of seeds is generally done in autumn in a sunny place) and

(2) The asexual way (by cuttings or division of stock: the cuttings are taken in August on semi-hard wood). These cuttings, from 8 to 10 cm, are placed in a mixture of equal volumes of sand and manure compost. After rooting, they will be transplanted in March before being planted later in the ground. The recommended planting distances are: inter-plant (40 to 50 cm), inter-row (80 cm). The optimal planting density is 25000 to 35000 plants per hectare.

Irrigation and crop care

absinthe producers irrigate 2 to 3 times a fortnight during the dry season, with no water supply during the winter. In addition, a pruning at 10 cm from the ground is necessary each year to renew the stems bearing branches to be harvested. This pruning takes place

 

usually in early spring. Maintenance pruning is sometimes necessary to remove diseased, dried out or overly long wood. Hoeing is a necessary operation to aerate the soil and reduce water evaporation. Weed control aims to eliminate competition between the crop and weeds and is usually done at the same time as hoeing.

Fertilization

The crop can remain in place for up to 10 years. A supply of organic matter in the form of manure is recommended in autumn. The amount to be applied varies according to the organic matter content of the soil; generally up to 50 tons/ha of manure can be applied. Mineral elements are applied before the vegetation starts to grow at a rate of 160 to 180 units of nitrogen divided into 2 or 3 applications; 100 to 120 units of phosphorus in a single application and 140 to 160 units of potash in a single application. In the first year, only 100 units of nitrogen will be applied; half after rooting the cuttings in late June and half in July

Enemies of the crop and means of phytosanitary control

The most common disease in absinthe is rust. It is characterized by small brownish pustules that later turn black and release brown spores that give the brown appearance of the disease. Concerning the pests, colonies of yellow aphids can attack the leaf of wormwood.

Harvest

The harvest is normally done from the second year during flowering in July and August. The cutting is done manually with a sickle, but it is possible to make a mechanical cut.

However, it is possible to make a cut in the first year to help the formation of the cutting table (cutting level). The yield in this first year hardly exceeds 8 to 10 tons/ha of fresh material, on the other hand, from the second year of production, yields are 30 to 40 tons/ha of fresh material. At drying, the yield is reduced by 75% by weight; this means a yield of 10 tons/ha of dry matter, of which 40 to 45% is pure leaves.