Ephraim Weil – Agronomist, Plant Protection Specialist, Hishtil

Spreading the knowledge of organic cultivation

The demand for organic products increased significantly over the last decade. Hishtil, one of the leading producers of organic rooted\unrooted cuttings of herbs, has seen this trend developing as they are involved in it from scratch. They started to grow a selection of their assortment organically 10 to 15 years ago and now, they have nearly all their varieties, including lavender, also available as an organically grown product. As more and more growers all over the world are looking into the option of organic cultivation, Hishtil started to spread the knowledge and experience they gained at their nursery in Israel. 

Demand for organic
According to Ephraim Weil, Agronomist, Plant Protection Specialist at Hishtil, the demand for organic cuttings and young plants increased in many countries. "In recent years, we are seeing that a rising number of growers are looking for organically grown plants, this as a result of, on the one hand, that increasingly more types of pesticides are not allowed anymore and that the social pressure to limit the use of pesticides is rising in more and more countries."   

Spreading the knowledge 
Since the very beginning, so for over 40 years now, Hishtil has been in close contact with their growers and spreading and sharing their knowledge and experience about growing their products. Also for organic cultivation, they are eagerly sharing it with their growers all over the world, which enables growers to better succeed. "Initially, we only had 10 crops that we also grow organic, now we have about 20 to 30 crops.” Hishtil has a lot of nurseries all over the world growing their products. “It is great to see that in some countries like Mexico and South Africa, where organic cultivation is still quite new, it is being picked up rapidly, not only by the growers, but also by the industry in general."

Coping with pests
So, how to cope with pests? Below, and also published earlier in this article on IsraelAgri, Weil explains.

"The main conventional method to cope with pests is chemical spraying, but over the last few decades and particularly in recent years, there have been more and more reasons to reduce chemical control and shift to environment friendly methods. Environmental pollution, employee safety, hazards for pollinators, strict regulations regarding the use of chemicals, and the amount of pesticide residues permitted in consumable products, entire groups of very efficient chemicals that have been banned – all of these have led to developing an alternative way to control pests, "integrated pest management" (IPM).

IPM means pest management in a way that minimizes the use of chemicals and emphasizes natural and low-toxicity methods like pest trapping, low-risk pesticides, and other practices. The main component in IPM is biological control that is defined as the reduction of pest populations by the use of natural enemies that in this context are also called "beneficials".

Predatory mite Phytoseiulus persimilis. "We would like to acknowledge Bio-Bee Biological Systems the IPM company we work with for their routine assistance and for the photos in this article."

There are different kinds of enemies who have different strategies of attacking their prey. Two main strategies are those of predators and parasitoids. Predators are species that feed directly on their prey and by doing so kill them. As they consume a large number of pests, they manage to reduce or even eradicate the entire pest population on the specific plant or crop. Another group is the parasitoids who lay their egg on or within a single pest. The egg hatches, the young stage develops, and in this way, it kills the pest from the inside.

An example of a predator is the predatory mite Phytoseiulus persimilis, an obligate predator highly specific to spider mites. Once established, it can keep the plants free of mites. Another predatory mite is Amblyseius swirskii, a generalistic predatory mite used worldwide against whiteflies, mites, and thrips. A parasitoid example is the parasitic wasp Aphidius colemani that controls aphids by laying its eggs within the aphid's body.

Parasitic wasp Aphidius colemani

In the wild, these natural enemies are active, attack pests, and create a state of equilibrium between themselves and the pests, reducing the damage caused by the pests and keeping it at a low level. In intensive commercial growing, this is not enough. Plants that are to be commercially distributed can't be infested with pests even at a low level like in nature. If these plants, whether whole plants, transplants or cuttings, are to cross borders between countries, the requirements for material that is pest-free are much stricter.

This situation leads the grower to integrate several pest control methods: in addition to the use of beneficials, they also use pesticides. This integration is very challenging, as most conventional pesticides can't be used because they would harm, disturb or kill the beneficials. Only a limited list of pesticides can be used. Such a list requires extensive knowledge, actual trials, and an updated database covering the influence of the different pesticides on every specific beneficial, in order to confirm that it won't cause harm at any of the life cycle stages.

In some circumstances the beneficials "don't do the job". They can't manage to reduce the pest population. There can be many reasons for this, including environmental conditions such as humidity, day length, temperature, etc., that make it hard for them to become established. Another possibility is the unsuitability of the enemy to the pest (for example, the parasitic wasp Aphidius colemani. Although it is polyphagous and attacks over 40 species of aphids, there are more than 400 species that affect commercial crops, and all of the other species won't be attacked by this wasp). When these things happen, the grower may consider the use of chemicals.

Predatory mite Amblyseius swirskii

One of the basic principles for the success of biological pest control is the establishment of the beneficials on the plants. After spreading them on the plants they lay eggs, become established, and the next generation then emerges. To succeed in this establishment process, the beneficials need optimal growing conditions as already mentioned above. In propagation nurseries that grow mother stock plants for the use of cuttings, this becomes more complicated, as the practice of producing cuttings is done by routine trimming of the plants, which means routinely disturbing the beneficials. Therefore, we at Hishtil have to collect data that is unique to our conditions and implement them in our production process.

Biological control is very challenging anywhere and anytime, and requires a lot of attention to details, growing conditions, agricultural practices, plant stages, etc. In a propagation nursery, the challenge is even bigger and in the propagation of herbs or organic herbs, it is bigger still. Along the way, we may experience successes and failures too, but Hishtil, as a leading company in its field and in order to fulfill its mission "to improve the quality of food and the environment", is obligated to stick to anything that will ensure we can live in a better world."

For more information:
Ephraim Weil
Email: efiw@hishtil.com    


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