Shipping augmentative biocontrol agents

discusses the procedures implemented by the companies to assure quality, the documents required and provided currently, and the challenges to the safe transportation of beneficial organisms.


Introduction
The majority of worldwide shipments of arthropods is done by specialized companies that produce and distribute beneficial insects, mites and nematodes for augmentative biological control of pests on agricultural crops. For decades, thousands of shipments of these beneficials have been made every year, without major incidents. This is due to the existence of a highly professional industry, mainly composed of small and medium-sized enterprises, that have established qualified research and development departments, which continuously perform extensive studies to develop optimal transport and storage conditions for the different beneficial species. These arthropods are intended to be released mainly in agricultural crops (often in greenhouses) to safeguard the crops from pest damage (1). In this article we discuss the relevance of augmentative biocontrol; the current status of how these arthropods are transported and traded; the potential risks/problems related with transport; and the future challenges. Only issues concerning the transport itself are discussed, since the import/export and release permits for biocontrol agents (BCAs) are already covered by regulations at the national level (2) and compliance with the regulations needs to be attested by the documents included with each shipment.

Relevance of augmentative biocontrol
Global food production systems are facing the challenge of satisfying the demands for increased crop productivity while maintaining or increasing their environmental and economic sustainability (3). The use of mass-reared natural enemies, predators and parasitoids of pests, has 41_1_05_Vila -pre-print 3/15 been shown to be an effective and a sustainable alternative to pesticide use from an environmental and economic perspective. Biological control re-establishes and enhances natural pest regulation mechanisms as they occur in natural ecosystems. As such, biological control is a main contributor to sustainable agriculture, and it is a key element to achieving the ambitious goals of the European Green Deal (4).
Today, the augmentative release of beneficial arthropods is applied in many areas of agriculture such as fruit and vegetable crops, cereals, maize, cotton, sugarcane, soybean, grapes, and many greenhouse crops (1). It has allowed substantial reduction of chemical pesticide use. A good example is the published analysis of chemical pesticide residues on Spanish peppers upon import to Germany, both before and after the

Market for the biological control agents
Since the 1960s, biological control through the augmentative release of predators or parasites grew from a scientific activity to a reliable way of crop protection and a commercially viable alternative to pesticides.
Years of fundamental and applied research, together with considerable investments by the private sector, have made this success story a reality.
Today, there are about 500 commercial producers of BCAs worldwide (1).
More than 170 species of invertebrate natural enemies are used in augmentative biological control in Europe (6); the number increases to about 219 arthropod species when considering the worldwide scenario (7). Of these, about 32 species are widely used in crop protection (2).

Potential risks of trade in beneficial insects, mites and nematodes for biocontrol
Beneficial insects, mites and nematodes for augmentative biocontrol have been transported in increasing numbers for more than 50 years. The only minor exception would be the rare and usually limited problems described with the use of mites (10,11), due to allergic reactions that can occasionally happen in a small percentage of people that are sensitive to dust mites. These are not different to other allergies produced by foods or fibres (for instance people allergic to certain fabrics). Most, if not all of these cases, happen only when sensitive people are exposed during prolonged time in conditions where the mites are active. For instance, cases have occurred after many days of handling mites directly while distributing them in the crop (12). For most of these cases a simple dust-preventive mask and gloves suffice as protection. However, any allergic situation is very improbable during transport due to the packaging standards (see detailed procedures below).
41_1_05_Vila -pre-print 5/15 There are very low environmental risks associated with these beneficials during transport because the packaging standards minimizes the possibility of accidental releases during transport. More importantly, any environmental risk associated with end use is already covered by regulations of the importing and exporting countries, as these beneficials are authorized to be released in the crops by the national authorities both at the shipping country and at destination.
Conformity with these regulations is demonstrated by the permits and documents included with each shipment.
Many commercial BCAs are endemic in the markets in which they are sold, so occur naturally in the environment. Exotic species are subject to extensive risk assessment, carried out with international participation, before import permits are provided (13). 41_1_05_Vila -pre-print 7/15

Quality assurances
Since the fragile mites and insects can be easily affected by environmental conditions during packaging, storage and transport, thereby compromising their performance in the field, major companies have defined and implemented standard operational procedures (SOPs) to guarantee their quality (16). Two major aspects are 1) the need to ensure that a cool chain is maintained during transport, to avoid mortality and/or quality loss, and 2) the arrival within a few days using the fastest possible route and avoiding delays. The range of optimal temperatures is species dependent. Insulating packaging, icepacks and Relative humidity (RH) is a further key parameter, and each species is packaged within different substrates with specific RH, which needs to be adjusted according to the distance of the destination and means of transport.
For some products, carbon dioxide (CO2) is a third parameter that needs consideration in transport. The concentration of carbon dioxide, often correlated with the level of oxygen availability inside insulating boxes or in the transport vehicle, can reach levels harmful to the living beneficials, leading to reduced vitality of the populations or even mortality.
Monitoring of the temperatures in the insulating boxes and/or in the transport vehicle is generally performed with Data Loggers (Fig. 1), and 41_1_05_Vila -pre-print 8/15 for some products loggers measuring RH and/or CO2 are included as well.
The SOPs typically comprise at minimum quality control (QC) measurements for three stages: 1. after production and before formulation and packaging 2. QC of the packaged products before shipment 3. at the subsidiary/distributor facilities after transport.
QC guidelines for natural enemies compare their quality relative to long-term production standards as well as to wild populations of the same species (16). These guidelines are a result of an intensive cooperation between researchers and the BCA industry. Often the defined threshold values of the examined parameters by the producers (numbers per container, morphological and/or molecular identification, fecundity, etc.) need to exceed the minimum requirements described by the IOBC (16).

Packaging
Beneficial insects, mites and nematodes are packed in multiple layer packaging with well-closed inner containers or sachets. According to the species, different containers are used: plastic or cardboard bottles or tubes sealed with a ventilated cap, bulk bags (paper or plastic) and blisters. Some species of predatory mites are packaged in individual sachets, which are made with a breathable paper or a compostable foil.
For transport, all these containers are placed inside polystyrene boxes, together with ice packs (frozen at least 24 h in advance), as well as low weight insolation and buffer materials (see Figure 1 as an example).
The boxes are completely sealed, and sometimes additionally placed inside a cardboard container. For certain species of mites, small openings are included for ventilation (Fig. 1). The size and thickness of the polystyrene box, the number of product units, number and type of icepacks and buffer packs is adjusted according to the species, destination and means of transport.
41_1_05_Vila -pre-print 9/15 All the products are labelled with unique codes for traceability to the batch of production and packaging, as well as with the name of the species, quantity of individuals, adequate range of temperatures for storage, pictograms advising how to handle and release the material, etc. The specific information provided on the label is often regulated by national authorities, and so may differ by destination.
[Place the Figure 1 here] A major problem for the sector is the high price for air shipment of beneficials, which often is much higher than for shipments of other materials. An additional challenge is finding courier companies, since most of them implement blanket rejections of all living animals in their transport rules; they do not differentiate between transporting tigers and beneficial arthropods (17,18 Requirements can also be used by courier companies.

Current transport situation and challenges
An additional problem that has been affecting transport in general, and the shipping of BCAs in particular, is the restrictions imposed by the COVID-19 pandemic. Limitation in flight availability has strongly compromised the transport of BCAs. However, the pandemic has highlighted more than ever the correlation between human health, environmental protection, and economics, as well as the need to create/maintain good local agricultural production. It is in this framework that biological control plays a critical role by enabling a more regenerative agriculture.

Conclusions
Transport of BCAs from centralized production points is essential to the success of agricultural pest management across markets in many different countries. By assuring the right transport conditions and minimizing transport time, the transport sector has a vital role to play in contributing to the efficient production of safe and healthy food for the growing world population. Grower motivation, legal requirements, and social demands in favour of food and ornamental plants produced with less or no pesticide residues will stimulate an increase in the worldwide trade of beneficial insects, mites and nematodes, used in augmentative biological control.
41_1_05_Vila -pre-print 11/15 Despite the often-limited knowledge about these beneficial arthropods by the transport services, which may generate problems, many transport organisations have worked with the major biocontrol companies to safely arrange thousands of shipments internationally. However, rejection of shipments of beneficial mites and insects by courier companies under blanket bans on transporting live animals could compromise this success story. A better understanding of the contribution of these arthropods to the production of safe and healthy food, and their general innocuousness, would be desirable. For this purpose, any possible guidance for regulatory authorities would be welcome, as long as it is fit for purpose and does not generate irrelevant hurdles which could compromise the required transport and trading of these beneficials.