The overzealous and indiscriminate use of most of the synthetic fungicides has created different types of environmental and toxicological problems. Recently, in different parts of the world, attention has been paid towards exploitation of higher plant products as novel chemotherapeutants in plant protection. The popularity of botanical pesticides is once again increasing and some plant products are being used globally as green pesticides. Pyrethroids and neem products are well established commercially as botanical pesticides and recently some essential oils of higher plants have also been used as antimicrobials against storage pests because of their relatively safe status and wide acceptance by the consumers. Some of the volatile oils, which often contain the principal aromatic and flavouring components of herbs and spices, have been recommended as plant based antimicrobials to retard microbial contamination and reduction in spoilage of food commodities. In the context of agricultural pest management, botanical pesticides are best suited for use in organic food production in industrialized countries but can play a much greater role in the production and post harvest protection of food products in developing countries.

https://file.scirp.org/pdf/AS20120300013_23840567.pdf

Efficacy of plant extracts in plant disease management

Today, researches are focusing on the discovery of new therapeutic substances of natural origin with possible low or no toxicity to human, animal and environment, based on ethnomedical and ethnoveterinary practices.Vernonia amygdalina is a shrub that has been commonly known as bitter leaf due the bitter taste of the leaves. It is widely used as a daily green vegetable or herb to treat malaria and diabetes. The potential of V. amygdalina was first noted when scientists observed chimpanzees use the pith of this shrub for self-deparasitization. Since that discovery, subsequent researches had unveiled more and more bioactivities possessed by different extracts of this plant such as antidiabetic, antibacterial, antimalaria, antifungal, antioxidant, liver protection and cytotoxic effects which are beneficial to health. Compounds including steroid glucosides, sesquiterpene lactones and flavonoids which contributed to its bitter taste and bioactivites have also been isolated from this plant. Toxicology studies documented on this plant shows that V. amygdalina has low or no toxicity thereby supporting the safe use of this plant for the benefits of health.

	 

	Keywords: Vernonia amygdalina, bioactivities, antidiabetic, antioxidant, liver protection.

Vernonia amygdalina, an ethnoveterinary and ethnomedical used green vegetable with multiple bio-activities.

Effectiveness of plant extracts on suppression of damping-off and wilt diseases of lupine (Lupinus termis Forsik)

The peach is one of the most important global tree crops within the economically important Rosaceae family. The crop is threatened by numerous pests and diseases, especially fungal pathogens, in the field, in transit, and in the store. More than 50% of the global post-harvest loss has been ascribed to brown rot disease, especially in peach late-ripening varieties. In recent years, the disease has been so manifest in the orchards that some stone fruits were abandoned before harvest. In Spain, particularly, the disease has been associated with well over 60% of fruit loss after harvest. The most common management options available for the control of this disease involve agronomical, chemical, biological, and physical approaches. However, the effects of biochemical fungicides (biological and conventional fungicides), on the environment, human health, and strain fungicide resistance, tend to revise these control strategies. This review aims to comprehensively compile the information currently available on the species of the fungus Monilinia, which causes brown rot in peach, and the available options to control the disease. The breeding for brown rot-resistant varieties remains an ideal management option for brown rot disease control, considering the uniqueness of its sustainability in the chain of crop production.

/pdf/peach-brown-rot-still-in-search-of-an-ideal-management-1ygprnwcwb.pdf

Peach Brown Rot: Still in Search of an Ideal Management Option

The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agroproduce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens’ resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques and emphasized the efficacy of plant-based pesticides for control of mycoinduced storage rots of tubers and agricultural products in the tropics.

Efficacy of plant-derived pesticides in the control of myco-induced postharvest rots of tubers and agricultural products: a review.

A study on the use of ginger ( Zingiber officinale ), aloe ( Aloe ve ra), bitter kola ( Garcinia cola ) and neem ( Azadirachta indica ) extracts in the control of root rot of cowpea caused by Pythium aphanidermatum was carried out in vitro and in the field ( in vivo ). They were evaluated for their antifungal activity over P. aphanidermatum , a rot fungus of many economic crops. Vegetative growth values over the fungus at 40, 60, 80 and 100% concentrations were generally low compared with the control, complete inhibition of fungal mycelia growth was exhibited at all concentrations in ginger extract. Aloe at 60% completely inhibited mycelial growth; this was followed by bitter kola with only retardation of mycelial growth while neem was the least effective. Highest mycelial dry weight was noticed on bitter kola extract but more sporangia formation in neem after a prolong incubation. However, the extracts were sparingly effective for a short period on the field experiment. A statistical evaluation of variance showed a significant difference between mycelial radial growths values recorded on the various plant extracts concentrations used compared with the control.

/pdf/efficacy-of-four-plant-extracts-in-the-control-of-root-rot-18btbjr9iw.pdf

Efficacy of four plant extracts in the control of root rot disease of cowpea (Vigna unguiculata [L.] Walp).

Aqueous leaf extracts were obtained from the matured leaves of three medicinal plants: namely, bitter leaf (Vernonia amygdalina), Senna alata, and lemon grass (Cymbopogon citratus). They were evaluated for their antifungal activity over Fusarium sp, a pathogenic spot fungus of many economic crops. Vegetative growth values for Fusarium sp at 1.5%, 2.0%, 2.5%, 3.0% and 3.5 % concentrations were generally low compared with the control; complete inhibition of fungal mycelial growth was exhibited with 3.0% and 3.5% concentrations of Senna alata extract. A statistical evaluation of variance showed a significant difference between mycelial radial growths values recorded on the various plant extracts concentrations used compared with the control. Plant extracts readily available and affordable and environmentally friendly in the control of Fusarium sp. Plant extracts could serve as a reference material in further studies involving other pathogens of economic crops.

S. A. Emua

Papers

Efficacy of four plant extracts in the control of root rot disease of cowpea (Vigna unguiculata [L.] Walp).

Effect of aqueous leaf extracts on a spot fungus (Fusarium sp) isolated from compea.