Neem oil and spinosad

Neem oil or Neem oil.

Neem oil from the neem tree is another natural insecticide grown in Africa, India and South America. This insecticide is recommended in organic agriculture as an alternative to chemical pesticides. A report by France 2 presented this insecticide on 8 January 2018 on the 8 o’clock news and was repeated on the web under the title “Pesticides: the seed of hope from Benin” without specifying its disadvantages. In France, following intense lobbying, the use of a product containing neem oil, NEEM AZAL TS, had already been authorised for a period of 120 days (until 30 June 2017) (1). It has been authorised again since 5 December 2018 for the cultivation of cucumbers, tomatoes and green and flowering plants (8). Another formulation, azatin, is authorised for crops grown under cover in soilless conditions.

It is astonishing to note that the proponents of organic farming who hold environmental protection sacred advocate the use of neim oil, even though it is known to be an endocrine disruptor (2) and a danger to adult bees and their larvae (3). Several studies have shown that the active substance in neem oil, azadiractin, is a genotoxic carcinogen (4 – 5 – 6).

Azadirachtin is absorbed into the plant tissues of crops and then transported by the sap: it is therefore a systemic pesticide. Azadirachtin causes liver and lung legions in some mammals (7). Studies have shown that neem oil is toxic to fungi, insects and nematodes (8). Its use by farmers requires the wearing of gloves, boots and a full protective suit (Chemical Protective Suit, with double zip closure). Thus, it is not only in conventional agriculture, as presented in some reports on France 2, where the wearing of cosmonaut suits is advised.

Neem oil is present in various cosmetic preparations, to fight lice, in anti-dandruff shampoos… In garden centres, there are ranges of products containing neem oil declared “natural” or “organic”, some preparations being in the form of sprays to be introduced into a sprayer. It is easy to find neem oil on websites specialising in the sale of natural products and how to use it as an insecticide.

For amateur gardeners, neem oil must therefore be used with caution, taking into account its disadvantages, without banishing it from the list of substances that are essential for fighting certain pests.

Recommendations for the use of NEEM AZAL TS according to its producer on the E-Phy website :

• – Wear coveralls (cotton/polyester 35%/65% – weight at least 230 g/m²) with water repellent treatment and, in case of contact with the treated crop, nitrile gloves certified to EN 374-3.
  
  In the case of application with a spray gun
  – during mixing/loading
  – Nitrile gloves certified to EN 374-3;
  – Protective suit of category III type 4 or 3 (depending on the level of protection recommended during the application phase);
  OR
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water-repellent treatment;
  – Partial PPE (blouse or long-sleeved apron) of category III and type PB (3) to be worn over the above-mentioned suit;
  – during application: without intense contact with the vegetation
  Low crop (< 50 cm)
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water repellent treatment;
  – Protective boots certified to EN 13 832-3 ;
  High crop (> 50 cm)
  – Nitrile gloves certified to EN 374-3 ;
  – Protective suit category III type 4 with hood;
  – Protective boots certified to EN 13 832-3;
  – during application: intense contact with vegetation
  – Nitrile gloves certified to EN 374-3 ;
  – Protective suit category III type 3 with hood;
  – Protective boots certified to EN 13 832-3;
  – during cleaning of spraying equipment
  – Nitrile gloves certified to EN 374-3 ;
  – Protective suit category III type 4 or 3 (depending on the level of protection recommended during the application phase);
  OR
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water-repellent treatment;
  – Partial PPE (gown) of category III and type PB (3) to be worn over the above mentioned suit;
  
  – EUH208: Contains azadirachtin. May produce an allergic reaction.
  
  – 48 hours.
  – Do not store for more than 15 months.
  
  – SP 1: Do not contaminate water with the product or its packaging. Do not clean application equipment near surface water. Avoid contamination via drainage systems from farmyards or roads.
  
  – SPe 8: hazardous to bees. To protect bees and other pollinating insects, do not apply during flowering and exudate production periods. Do not use in the presence of bees. Do not apply when weeds are in flower.
  
  – May cause harm to beneficials. May harm insect pollinators. Avoid unnecessary exposure.
  
  General information on good protection practices may be made available to the user:
  – the use of suitable and well-maintained equipment and the use of collective protection are the first preventive measure against occupational risks, before the use of individual protection
  – the wearing of dedicated overalls or PPE must be associated with hygiene reflexes (e.g. hand washing, showering at the end of treatment) and rigorous behaviour (e.g. dressing/undressing procedure).
  – the cleaning and storage procedures for reusable work suits and PPE must comply with their instructions for use.
  
  For each use included in the list of authorised uses, the conditions of use of the product must be such that the maximum residue limits are respected.
  
  In the case of application with an airblast sprayer
  – during mixing/loading
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water repellent treatment;
  – Partial PPE (gown or long-sleeved apron) of category III and type PB (3) to be worn over the above-mentioned overalls;
  – during application
  If applying with tractor with cab
  – Working suit made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water repellent treatment;
  – Nitrile gloves certified EN 374-2 for single use, in case of intervention on the equipment during the spraying phase. In this case, the gloves must only be worn outside the cab and must be stored outside the cab after use;
  If applying with a tractor without a cab
  – Protective suit of category III type 4 with hood;
  – Nitrile gloves certified to EN 374-2 for single use, in case of intervention on the equipment during the spraying phase;
  – during the cleaning of the spraying equipment
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water-repellent treatment;
  – Partial PPE (gown or long-sleeved apron) of category III and type PB (3) to be worn over the above-mentioned suit;
  
  In the case of application with a boom sprayer
  – during mixing/loading
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water repellent treatment;
  – Partial PPE (gown) of category III and type PB (3) to be worn over the above-mentioned suit;
  – during application
  If applying with tractor with cab
  – Working suit made of 65% polyester/35% cotton with a weight of at least 230 g/m² with water repellent treatment;
  – Nitrile gloves certified EN 374-2 for single use, in case of intervention on the equipment during the spraying phase. In this case, the gloves must only be worn outside the cab and must be stored outside the cab after use;
  If applying with a tractor without a cab
  – Work suit made of 65% polyester/35% cotton with a weight of at least 230 g/m² with water repellent treatment;
  – Nitrile gloves certified to EN 374-2 for single use, in case of intervention on the equipment during the spraying phase;
  – during the cleaning of the spraying equipment
  – Nitrile gloves certified to EN 374-3 ;
  – Working overalls made of 65% polyester/35% cotton with a weight of 230 g/m² or more with water-repellent treatment;
  
  – Partial PPE (gown or long-sleeved apron) of category III and type PB (3) to be worn over the above-mentioned overalls

Here is what the ANSES says about the toxicity of azatin:

“C2: Serious eye damage and eye irritation – Category 2
C2: Toxic to reproduction – Category 2
TCC1: Hazards to the aquatic environment – Chronic hazard, category 1
AT: Warning statement : Caution
AT: Warning statement: Caution
AT: Signal word: Warning: Caution
risk phrase
H319: Causes severe eye irritation
H361d: May cause harm to the unborn child
H410: Very toxic to aquatic organisms, causes long-term adverse effects»

Spinosad

Spinosad is a natural insecticide derived from the culture of a soil-dwelling actinomycete bacterium (Saccharopolyspora spinosa). It is a mixture of two spinosyns (A and D) which differ from each other by the presence of a methyl group (a). It is a neurotoxicant acting by contact or ingestion. In organic agriculture, it is more widely used than neem oil, especially on fruit trees and vegetables. It is effective against certain pests, in particular cabbage maggot, Colorado potato beetle, codling moth larvae that burrow into apples and pears, olive maggot and diamondback moth caterpillar (Plutella xylostella) which can also infect radishes and turnips. Spinosad preparations are also used to control leafminers, spider mites, mosquitoes and ants.

Although it is permitted in AB, it is highly toxic to pollinators. It is extremely toxic to bees with an acute LD50 (50% mortality in susceptible individuals) on contact of 0.0029 µg/bee (10). Due to its high versatility, it is also toxic to some beneficial insects such as aphid parasitoid micro-hymenoptera (both adults and larvae parasitizing the host), mirids which are small predatory bugs especially of aphids and whiteflies. Ladybirds and lacewings would be less susceptible. It is of low toxicity to mammals, birds and crustaceans, earthworms and moderately toxic to aquatic organisms. Repeated use of spinosad in organic farming may lead to the development of resistant strains.

A study conducted by the University of Melbourne and published in ELife magazine on 22 February 2022 shows that low chronic exposure (0.2 parts per million) to spinosad has profound effects on beneficial insect species (11).

Most preparations containing spinosad are reserved for organic professionals, but some preparations for sale in garden centres contain spinosad, such as bait gels for ant control. It should be noted that there is a more stable spinosad derivative developed by chemists, spinetoram, but it is reserved for professionals.

a) Methylation is a chemical modification consisting of the addition of a methyl group (CH3) to a substrate.