Protecting Crops from Nematode Pests:
Using Marigold as an Alternative to Chemical Nematicides
A New Generation Insecticide: Nematicide
Botanical Source: Tagetes erecta L.
Plant Part Used: Root
Active Ingredient: Alpha-terthienyl
Other Names: Alpha-Terthienyl; 2, 5-Di(2-thienyl)thiophene, 2, 2': 5', 2''-Terthiophene, Terthienyl
CAS No.: 1081-34-1
Molecular Formula: C12H8S3
Molecular Weight: 248.39
Appearance: Fine brown powder
Harm of Nematode Pests
The primary soil-borne plant-parasitic nematodes impacting cropping systems are the rootknot, reniform, cyst, burrowing, and lesion nematodes, all of which contain spear-like mouthparts used to puncture plant roots and obtain nutrients. These nematodes cause significant economic damage to a wide variety of crops. After crops are infected with nematodes, crop yield and quality are reduced, either directly from root deformation caused by nematode feeding or indirectly from predisposition to infection by other pathogens that results from nematode penetration into the roots. The methods most frequently used for managing nematodes in agriculture include rotating crops with plants that are not hosts of plant-parasitic nematodes, using resistant plants if available, and applying chemical nematicides.
Now KINGHERBS' Marigold root extract of Alpha-terthienyl can solve this problem.
Most synthetic nematicides are expensive and because of their toxicity have adverse effects on nontarget organisms. The negative aspects of soil fumigants and nematicides and the increasing demand for organic produce and less environmentally harmful agricultural practices make marigold a potentially valuable alternative to chemical nematicides for nematode management.
It is clear that marigold can be used as a substitute for synthetic nematicides. In some instances, marigold can reduce nematode populations at greater soil depths than soil fumigation. In addition, marigold is more environmentally friendly than chemical nematicides because it does not repress other soil microorganisms. However, to successfully incorporate marigold into an integrated nematode management program it is important to select a marigold variety that is effective against the locally occurring nematode populations.
Mechanism by which marigold root suppresses nematode pests
Studies have found that they can be highly toxic to plant-parasitic nematodes and are capable of suppressing a wide range of nematode pests. The key mode by which marigolds suppress plant-parasitic nematodes is through a biochemical interaction known as allelopathy. It has nematicidal, insecticidal, fungicidal, antiviral, and cytotoxic activities, and it is believed to be the main compound responsible for the nematicidal activity of marigold.
The nematicidal activity of marigold has been detected in roots of growing plants but not in root or leaf extracts. Some studies have shown that these nematicidal properties result from a sequence of events in the marigold roots triggered by penetration and movement of nematodes through the root tissue, and the end product of these reactions is thought to kill nematodes. Thus, marigold is believed to be most effective in suppressing plant-parasitic nematodes when actively growing.
Currently, researchers have evaluated marigold for its ability to reduce the occurrence of aphid-borne non-persistent viruses and suppress weed, insect, and nematode pests directly through modification of the cropping environment and enhancement of beneficial organisms. We believe that to optimize their use in integrated pest management programs, cover crops should not be used solely to mitigate problems caused by plantparasitic nematodes, but rather used simultaneously to help suppress multiple pest organisms and provide other benefits to a farming operation.
KINGHERBS LIMITED; MS. CARA SHAW