Forest is an integral part of human livelihood on Earth providing benefits at local, national, and global levels. Forest health is very important to satisfy human needs in long run without deteriorating its quality. However, forest quality is deteriorating due to plenty of natural and anthropogenic disturbances, rampant competition from weeds, invasive/alien species, and the infestation of various pests and pathogens.
Production of forest products experiences a continual threat from the pest causing substantial losses. Pests are those organisms that harm human property significantly or likely to do so. The infestation of insects, pests, and pathogens is a serious problem, particularly in plantation and forest nurseries. The presence of fungal diseases weakens the condition of seedlings in forest nurseries. Some common Nursery pests are Aphids, Leafminers, Scale, Spider mite, Weevil, etc.
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| Beetles, budworms Source: mlive.com |
Types of Forest Nursery Pest
Based on feeding parts of forest nursery seedling, the pest is divided into 4 categories (Mathew, 1990).
❑ White Grubs/ Chaffers
❑ Root Feeders
❑ Defoliators
❑ Sap Suckers
Information on the insect pests of various tree species, their biology, and ecology are essential for developing suitable pest management strategies. Seedling production is an integral part of most tree growing programs and often a major part of most community forestry projects. So, seedling production nurseries should be monitor routinely and if abnormalities occur, treat before extensive damage occurs. Knowledge of pest symptoms is crucial to prevent possible loss from the spread of disease in its early stage.
Importance to control Forest Nursery Pest and Disease
Knowledge on pest and pathogen help to prevent pest and diseases and thus prevent in the reduction of plant density, caused stunted growth and ultimately death on severe. Also, it helps to increase forest production preventing lower production capacity, reduced yield, and quality of the product produced, and to prevent great economic loss/ human welfare. Controlling pests like insects, rodents, and parasites prevents potential carriers of diseases to spread.
Challenges in controlling Pest and Disease in Forest Nursery
Forest nurseries are a vital part of forestry programs. A healthy, disease-free, resistant nursery can provide required seedling for plantation. Various tree species can be raised in nurseries. Forest nurseries when managed improperly then it may be damaged by insects, nematodes, diseases, and cases limited production of the seedling.
Controlling insect pests and pathogens in the forest is a critical task of forest managers which demands expertise from different disciplines such as plant pathology, entomology, ecology, dendrology, mycology, taxonomy, silviculture, and forest management. This action is more challenging in natural forests compared to a plantation forest. Use of chemicals to control pests and pathogens limited on a small patch of forest or within forest nurseries due to difficulties in controlling over a large area. So, it is efficient to control the spread of pathogens before impacting a larger area by keeping healthy unaffected by implementing various tending and silvicultural operations.
Common Pest and Diseases of Forest Nursery
Some common Pest and Diseases of Forest Nursery and their control measures are mention below:
Holotrichia consanguinea
(O- Coleoptera; F- Scarabidae)
Feed on rootlet and cortical tissues of the seedlings and causes the death of the seedlings.
Host: Acacia nilotica, Aibizia bebbek, Prosopis cineria
Control: Bed fumigation with bromochloropicrin and applying of phorate granules will decrease the white grubs.
Odentotermis obesus
(O- Isoptera, F- Termitidae)
Feed on roots and causes wilting of plants and finally lead to the death of plant nursery
Host: Acacia nilotica, Dalbergia sissoo
Control: Spraying of chloropyripause to the seedlings will help to control the termites in the nursery
seedlings.
Brachytrypes portentosus
(O- Orthoptera, F- Gryllidae)
Cause damage to seedling by scrapping the green matter on leaves, and also cut the young seedling lead to death.
Host: Tocomella undulata, Albizzia lebbek, Papileo demoleous etc.
Control: Flooding the tunnels with water and putting kerosene on the tunnel killed insects.
Hyblaea puera
(O- Lepidoptera, F- Hyblaeidae)
Causes one or more near-total or partial defoliation of teak over extensive areas annually. The major pest of teak plantation in Asia.
Host: Alstonia scholaris, Pterocarpus macrocarpus, Tectona grandis, Vitex spp.Control: Install light traps to monitor and trap adult moths. The spray of Neem oil or Pungam oil emulsion can be done 15-20 days interval.
Cryptothelia crameria
(O- Lepidoptera; F- Psychidae)
Causes serious Defoliation; Serious pest of Chir pine.
Host: Antocephalus cadamba, Mangifera indica, quercus incana, Shorea robusta
Leaf Feeders
Caterpillars, beetles, and grasshoppers are leaf-feeding insects.
Chrysomelids weevil common coleopteran defoliator feeding leaf margin irregularly causing extensive damage.
Control: Natural enemy birds, spiders, ants. Use of 0.2% Fenitrothion (sumithion), 0.1% carbaryl (Sevin).
Shoot boring insects
Scolytids and weevils are among the important shoot borers of seedlings. Both larvae and adults boreholes into the shoots causing seedling mortality.
Control: Removal of affected shoots and, maintaining low seedling density has been suggested.
Gall-forming Insects
Leaf and stem galls are produced by psyllids and wasps.
Control: Removal of affected shoots and application of a systemic insecticide such as dimethoate (Rogor) or monocrotophos (Nuvacron, Monophos) (0.01-0.02%); phosphamidon (Dimecron) (0.04%) or fenitrothion (Sumithion) (0.02%) or Tiamethoxam (Actra 0.25gm/1 lit) may be used to control the gall insects.
Root borers
Termites and several root-feeding beetles of the families Elateridae and Scarabaeidae attack the roots. White grubs (Holotrichia sp.) of the family Scarabaeidae also frequently attack roots.
Control: Soil drenching using a soil insecticide such as Phorate 2G may be effective in managing the white grubs.
Summary to Pest and Disease in Forest Nursery and their Control Measure
Pests are often a serious problem in forest nurseries in raising indigenous and exotic species for plantation programs. Prevention of the spread of pest and pathogens is the cheapest and most effective technique to maintain better health of the forest so, that ensures the regular and increased supply of forest goods and services. For that enough information on the correct identification of the pest, the nature of the damage, and the damage intensity of each pest and pathogen are essential for adopting a suitable management strategy. As far as pest management practices are concerned various strategies involving chemical, biological and silvicultural measures are attempted based on the nature of the pest and pathogen to protect forest plantations and nurseries. In Nepal, the use of new technology, strengthening and capacity building of forest technicians, and prevention and control of forest insect pests and pathogens should be given higher priority by concerned authorities for the benefits in the forestry sector in Nepal.
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