Despite our attention trees can be affected by diseases or pests and get sick ruining their aesthetics, they waste away and in some cases die. The main pests of plants can be divided into the following groups:
- animal parasites
- plant pests
- viruses and similars
This will include also many “useful” insects that produce a biological control of harmful species. Therefore, in order to respect the environment, human health and the natural balance of ecosystems, carefully interventions designed to identify the best time they are studied and planned and counteract the harmful agent.
The animal pests attack the plants and the fruits in several ways: by sucking sap by pricking the plant tissues with the stiletto mug; due to erosion by destroying the plant tissues with their chewing apparatus
All this causes mainly two devastating effects:
1) intracellular parasitism or removal of lymph between all ‘internal cell tissue forming yellow blob
2) occlusion of vascular bundles with clogging in the same zones that. Block the passage of the sap.
DISEASES
Type | Cause | Symptoms | Remedies |
Botrytis | Heat, humidity, water excess | whitish or black spots, rot | Avoid watering in the vicinity of the stem |
Chlorosis | Lack of iron and manganese, nitrogen and magnesium, excess water | Yellowing of leaves | Fertilize the plant |
Sooty mold | poor ventilation | Fouling dusty and blackish on the leaves | Wash the leaves with warm water, or water and milk |
Powdery mildew | Environmental humidity high, irregular watering, drops in temperature | Storage dusty or whitish | Improve and correct the culture conditions |
Rust | Excess moisture, inadequate temperature | orange spots, reddish or yellowish, warts | Remove damaged leaves and stems |
MAIN PESTS
INSECTS | STINGING SUCKER OF LINFA | CHEWER | DAMAGES AND DISEASES | HOST TREES |
MITES | • | Leaf remover | ||
APHIDS (plant lice) | • | Weakening discoloration distortions deformation honeydew sooty mold | Pine, spruce, acacia, maple, cedar, cypress, elm, linden, camellia, ivy | |
COCHINEAL (wad) | • | Foliar yellowing leaves sticky Defoliation | Pine, wisteria, juniper, ficus | |
COCHINEAL POWDER | • | Bleaching leaves leaves sticky Defoliation dieback branches | Palm, ivy. Ornamental plants | |
WHITE FLY | • | Enmeshment Yellowing leaves leaf Slowdown flowering sooty mold | Ornamental plants | |
RED SPIDER | • | Discoloration cobwebs Defoliation | Azalea, Camelia maple, elm, pine and fruit trees | |
Psyllid | • | Desiccation Fall leaves and buds honeyed | Albizia | |
Thrips | • | blacks dots on Yellowing leaves and fall dieback Deformation Discoloration | Ornamental plants | |
Leafhopper | • | Foliar browning and desiccation | ||
Phylloxera | • | Damage tuberosity roots Yellowing leaves and deformation Redness on the foliage dry yellow circular areas on the leaves | Holm, oak tree | |
METCALFA PRUINOSA | • | Weakening sooty mold contamination secretive | ||
LARVAE stripper O leaf-rollers | • | Braiding leaves with silky threads | ||
SNAILS | • | Weakening foliar fungal diseases leaf removal | ||
Bark beetle | • | under the bark Yellowing leaves leaf removal | Spruce | |
Gypsy moth | • | Browning leaf defoliation | Oak, birch, chestnut, hornbeam, beech, maple, poplar | |
Ants | • | leaf defoliation | Fir, acacia, maple, cypress, elm | |
NERATOSE | • | roots | Ornamental plants | |
Bark beetle OAK | • | Holes on the trunk and tunnels under the trunk | Oak tree | |
TINGIDE AMERICAN | • | yellowing leaves | plane tree | |
GALERUCELLA | Weakening, leaf removal | Olmo | ||
Red Palm weevil | • | Leaf removal | Pine | |
Pine processionary | • | Weakening, leaf removal | Pine | |
Oak processionary | • | Weakening, leaf removal | Oak tree | |
Cimex | • | Defoliation Alteration of chlorophyll | Poplar, willow, hawthorn and fruit trees | |
Chrysomela | • | Defoliation, slowing growth of lignification | Poplar, willow | |
Budworm Green | • | Defoliation, rolling leaves | Oak tree |
We will examine below in more detail some of the most common pests: pine processionary, aphids, cochineal.
PINE PROCESSONARY
Name: Traumatocampa (= Thaumetopea) pityocampa
Family: Thaumetopoeidae
Damage: This moth attacks all species of pine, but especially the black pine (Pinus nigra), Scots pine (Pinus silvestris), the maritime pine (Pinus pinaster), the Aleppo pine (Pinus halepensis) and various species cedar.
Description of the damage: The larvae feed voraciously of pine needles also causing defoliation of strong entity. Severe attacks can weaken the plant causing developmental delays. The stinging hairs of the larvae can cause skin irritation, eye and respiratory.
Natural enemies: the moth has several natural enemies, especially some Hymenoptera calcidi oofagi that, while having a significant role in limiting populations, fail to curb pullazioni.
APHIDS
Aphids are insects known as “plant” lice infesting nearly all ornamental plants, both indoor and outdoor, as well as the crops of agricultural interest. The adults, long from one to four millimeters, are covered with a thin integument of light yellow or green, or gray, or black. Some are winged forms that can migrate from one plant to another, reaching new plant hosts up to hundreds of kilometers away. The forms do not winged (wingless) instead, after losing his wings, focus all their resources in reproduction, thus giving rise quickly in crowded colonies. Aphids have great capacity for adaptation, especially in temperate climates. The plants can be attacked by different species, more or less frequent and dangerous, olifaghe or polyphagous (that feed on a few species or many), and often able to become resistant to insecticides. Fortunately, these pests have many natural enemies and it is on these antagonists that you are relying to contain infestations below the economic damage threshold in biological control programs.
Symptoms on plants: Aphids in addition to cause direct damage to the removal of lymph and with the emission of saliva that causes physiological changes, produce serious indirect damage as they are capable of transmitting the virus by feeding many of the infected plants first and then passing those healthy.
COCHINEAL
The Saissetia oleae (Oliv.) Also called “half peppercorn” for its emiglobosa form characterized by an H-back relief and for the dark coloring, cochineal is the most widespread and damaging of olive groves, but being polyphagous can develop at the expense of many plants of agricultural and ornamental interest.
Damage: Causes direct damage with the subtraction of sap and one indirectly caused by the release of honeydew. The latter is deposited on the underlying vegetation and favors the development of saprophytic fungi, crusting branches and leaves, reduces photosynthesis and gas exchange, causing a slow decline of the olive trees that causes a general decrease of the vegetative activity, resulting in poor flowering and fructification. It is essential before starting any type of treatment to identify the disease or parasite and then eradicate them adequately.
The plans disinfestation eliminate pests and parasites, but protect the flourishing of plants. The substances are spread by means of pumps and variable jet atomizers or nebulizers: formulations, usually aqueous emulsions, indicating on the label use in green areas, usually they have persistent activity and very low toxicity. Adequate and cyclical interventions avoid unpleasant new infestations. Rely only qualified personnel to quickly eliminate infestations and limit as much as possible to the economic damage caused by eventual death of the plant or crop loss.
Mario Alessi