Pesticide Usage in Scotland: Grassland and Fodder Crops 2017

Appendix 6: Integrated pest management

It is a requirement of the EU Sustainable use of Pesticides Directive (2009/128/ EC) ⁽¹³⁾ that member states should promote low pesticide input pest management, in particular Integrated Pest Management ( IPM).

The Directive defines IPM as follows “‘integrated pest management’ means careful consideration of all available plant protection methods and subsequent integration of appropriate measures that discourage the development of populations of harmful organisms and keep the use of plant protection products and other forms of intervention to levels that are economically and ecologically justified and reduce or minimise risks to human health and the environment. ‘Integrated pest management’ emphasises the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms.”

Information about the uptake of IPM measures by Scottish growers was collected alongside the 2017 grass and fodder crop pesticide usage survey. Similar data have been collected for other crop groups in previous years (vegetable crops 2015 ⁽¹⁵⁾ , protected edible crops 2015 ⁽¹⁶⁾ , arable crops 2016 ⁽¹⁷⁾ and soft fruit crops 2016 ⁽¹⁸⁾ ). In future, we intend to survey IPM uptake in each crop sector every four years. This monitoring programme is designed to describe adoption of IPM techniques in the main crop sectors and inform the Scottish Government of trends in uptake over time. These data can be used as an indicator of the success of Scottish Government funded IPM research, knowledge transfer and promotion activities.

It should be noted that in the main pesticide usage survey two samples are drawn, one based on holdings cultivating fodder crops (from which data are collected by personal interview) and another of holdings cultivating grass (from which data are collected by postal form, Appendix 4). These dual samples ensure that both fodder crops and Scotland’s large grass area are adequately represented in the sample. The IPM data presented here were collected only from the fodder proportion of the sample. This reflects that this data collection is more suited to personal interview than postal return and it ensures methodological consistency with previous IPM surveys. The fodder holdings surveyed also cultivated grass and the survey covers the IPM measures implemented on all grass and fodder production on those farms. Unlike the other statistics in this report, the figures reported in this section are not raised to produce national estimates, but represent only the responses of those surveyed. The IPM sample, whilst smaller than that sampled for the pesticide usage survey, represents all Scottish regions and farm size groups.

In total, IPM data was collected from 119 farmers, collectively growing 18,711 ha of crops (17,408 ha grass, 1,302 ha fodder). This sample represents eight per cent of Scotland’s 2017 fodder crop area (15,965 ha) and 0.4 per cent of the grass area (4,453,540 ha). Of these growers, 95 per cent did not have an IPM plan, three per cent of farmers completed their own IPM plan and two per cent had a plan completed by an agronomist on their behalf (Figure 38). Using an IPM plan helps growers to make the best possible, and most sustainable, use of all available methods for pest control. Whilst completion of a plan is voluntary, it also helps growers meet their legal obligation to take reasonable precautions to protect human health and the environment when using pesticides.

Figure 38: Percentage of respondents with an IPM plan – 2017

Farmers were asked about their IPM activities in relation to three categories; risk management, pest monitoring and pest control. Information was collected about all activities each grower conducted in relation to these categories and the responses are reported in the following sections. Despite the fact that the majority of growers did not complete an IPM plan, uptake of a wide range of IPM activities was encountered. The term ‘pest’ is used throughout to denote diseases, weeds and invertebrate pests.

Risk management

IPM programmes aim to prevent, or reduce, the risk of pests becoming a threat by minimising the likelihood of damage occurring that will require subsequent control. Table 32 presents an overview of the risk management measures adopted by those growers surveyed. Almost all of the growers sampled (97 per cent) reported that they implemented at least one risk management activity.

Sixty five per cent of growers used crop rotation to reduce the risk of pest damage. Rotation breaks the link between pest and host, reducing pest population build-up. It can also improve soil fertility and structure, and consequently crop vigour.

Table 32: Summary of responses to IPM risk management questions

Risk management activity	Percentage positive response
Crop rotation	65
Soil testing	84
Cultivation of seed bed	82
Cultivations at sowing	48
Varietal or seed choice	51
Catch and cover cropping	9
Protection or enhancement of beneficial organism populations	57
Any risk management activity	97

The majority of growers (84 per cent) tested their soil in order to tailor inputs to improve crop performance (Table 32, Figure 39). By testing for nutritional and pest status, farmers’ can make informed decisions about the inputs required and optimal crop choice for their land. Most testing encountered was for soil nutrients (76 per cent) and soil pH and/or lime requirements (soil buffering capacity) (19 per cent). Lower proportions of growers tested for soil pests such as nematodes, leatherjackets and wheat bulb fly (three, three and one per cent respectively) or soil-borne disease (clubroot, one per cent). Soil mapping and testing for earthworm activity were also each reported by one per cent of growers.

Figure 39 IPM: Soil testing - 2017

Note: 'other' includes soil mapping and testing for worm activity

The majority of growers (82 per cent) also reported that they managed their seed bed agronomy to improve crop performance and reduce pest risk (Table 32, Figure 40). Sixty one per cent increased soil organic matter. Eight per cent of growers used non-inversion tillage (primarily min till, with one report of strip tillage) and 10 per cent used direct drilling. Non-inversion techniques can preserve soil moisture and organic matter and reduce compaction and erosion. There is also evidence that it is beneficial for populations of earth worms and predatory ground beetles. Nineteen per cent employed rotational ploughing between periods of non-inversion cultivation; rotational ploughing can reduce weed burden and is also used to incorporate organic matter.

Six per cent of growers employed a stale seedbed technique for weed management. Stale seed beds allow weeds to germinate before sowing the next crop, these are treated with a herbicide, depleting the seed bank and resulting in lower weed pressure, and potentially pesticide use, in the succeeding crop. In addition, six per cent of growers reported other seed bed cultivations to improve crop performance, these included using mechanical methods such as disc harrowing, ploughing and rolling to attempt to reduce slug populations, rolling to combat leatherjacket larvae and application of lime to improve soil quality and crop health.

Figure 40 IPM: Seed bed cultivations - 2017

Note: 'other’ includes using mechanical methods for slug (harrowing and rolling) and leatherjacket (rolling) control and liming soil

Forty eight per cent of growers amended cultivation methods at sowing with the aim of increasing crop success (Table 32, Figure 41). Thirty four per cent under sowed with a secondary crop. Under sowing can increase soil fertility (when under sown with a nitrogen fixing crop), suppress weeds and provide a host for wildlife. Thirteen per cent varied the timing of sowing to reduce the risk from a range of pests; flea beetles, leatherjackets, pigeons, geese and weeds were all cited as reasons for changes in sowing date.

Some growers (10%) also increased sowing density to mitigate for damage from insect pests (flea beetle and leatherjackets), decrease competition from weeds or in order to improve crop establishment generally. One grower (one per cent of sample) reported that they increased sowing depth to decrease seed loss to pigeons.

Figure 41 IPM: Cultivations at sowing - 2017

Just over half (51 per cent) of growers reported that they considered risk management when selecting seeds and/or varieties (Table 32, Figure 42). Twenty four per cent used certified seed and one per cent tested home saved seed. These actions ensure that seed meets the required quality standards and is pathogen free. Eighteen per cent of farmers selected pest resistant varieties, to reduce damage and the need for pesticide input, and three per cent implemented varietal diversification to increase overall crop resilience to pests and environmental stresses. Twenty two per cent of growers used pesticide seed treatments to protect seedlings at crop emergence.

Only nine per cent of those surveyed sowed cover crops as part of their crop production cycle (Table 32). The cover crops were reported to improve soil quality, by ploughing in as a green manure, and/or to control weeds (seven and five per cent of the sample respectively).

Finally, 57 per cent of growers stated that they adopted techniques to protect or enhance populations of beneficial organisms (Table 32, Figure 43). Thirty one per cent left uncultivated areas, including fallow and grass margins, and five per cent planted wild flower strips. Thirteen per cent took part in an agri-environment scheme; the main scheme reported was the Scottish Government agri-environment climate scheme ( AECS) and actions primarily involved cultivation of wild bird seed mixes. A number of additional actions to support beneficial organism populations were also reported, some of which contributed to the Ecological Focus Area ( EFA) element of the direct payment scheme. These additional measures included; planting and maintaining hedges (six per cent) and woodland (three per cent), planting wild bird seed crops (three per cent) and maintaining species rich unimproved grassland (five per cent). Other minor categories included beetle banks, conservation grazing, protecting ground nesting birds and maintenance of ponds (five per cent in total).

Figure 42 IPM: Variety and seed choice – 2017

Figure 43 IPM: Protection and enhancement of beneficial organism populations – 2017

Note: 'other' includes established beetle banks, conservation grazing, protecting ground nesting birds and maintenance of ponds

Pest monitoring

In IPM, pests are monitored both to determine whether control is economically justified and to effectively target control options. IPM programmes aim to monitor and identify pests, so that appropriate control decisions can be made in conjunction with action thresholds. Table 33 presents an overview of the pest monitoring measures adopted by the growers surveyed. The majority of the growers sampled (94 per cent) reported that they implemented at least one pest monitoring measure.

Table 33: Summary of responses to IPM pest monitoring questions

Pest monitoring activity	Percentage positive response
Monitor and identify pests	93
Regular monitoring of crop growth stage	81
Setting action thresholds for crops	18
Use of specialist diagnostics	17
Any pest monitoring activity	94

Ninety three per cent of growers reported that they regularly monitored and identified pests and 81 per cent regularly monitored crop growth stages (Table 33). Pest monitoring information was primarily gained by seeking advice from a BASIS qualified agronomist (76 per cent) and by self-inspection by the grower (crop walking, 45 per cent). Other methods of pest monitoring, adopted by less than five per cent of those surveyed, included; press articles, technical bulletins, trapping, using risk warnings and attending discussion groups (Figure 44).

Figure 44 IPM: Monitoring and identifying pests – 2017

Seventeen per cent of farmers also reported that they used specialist diagnostics when dealing with pests that were more problematic to identify or monitor (Table 33). Thirteen per cent used field or pest mapping (predominately field mapping) to aid crop monitoring. Six per cent of growers used tissue testing services to monitor crop nutritional deficiencies and one per cent used clinic services to identify unknown pests.

Despite reporting regular agronomist inspection and crop walking, uptake of setting action thresholds was lower than encountered in other crop systems (18 per cent), reflecting the lower pesticide input to grass and fodder crops.

Pest control

If monitoring, identification, and action thresholds indicate that pest control is required, and preventive methods are no longer effective or available, IPM programmes aim to evaluate the best control method in relation to effectiveness and risk. Control programmes incorporate non-chemical methods alongside, or instead of, chemical control. The premise of IPM is that chemical pest control should be as targeted as possible and the risk of resistance development should be minimised. The effectiveness of the control programme should be reviewed regularly to gauge success and improved as necessary. Table 34 presents an overview of the pest control measures reported by the farmers surveyed. Ninety seven per cent of the growers sampled adopted at least one IPM pest control activity.

Table 34: Summary of responses to IPM pest control questions

Pest control activity	Percentage positive response
Non-chemical control used in partnership or instead of chemical control	87
Targeted pesticide application	51
Follow anti-resistance strategies	39
Monitor success of crop protection measures	82
Any pest control activity	97

Eighty seven per cent of farmers reported that they used non-chemical control in partnership or instead of chemical control (Table 34, Figure 45). The most common non-chemical method employed was mowing/topping grass to control a range of grass weeds (76 per cent). Thistles were the most common weed cited but mowing was also used to control rushes, ragwort, nettles and docks. Just over a third of farmers (36 per cent) used hand rogueing/manual weeding as part of their weed control measures. Hand weeding was primarily employed to control ragwort and wild oats. Some growers also used mechanical weed control (10 per cent). The mechanical control encountered was mostly for inter-row weed control in fodder swede and turnip crops, but was also employed to control rushes, thistles and bracken in grassland. A further 10 per cent of growers used intensive grazing to control weeds, with a single grower using grazing for disease control (removal of disease inoculum). There was lower uptake of mechanical control of insects (rolling for leatherjacket larvae, two per cent of sample) and pest trapping and use of biocontrol/biopesticides (both one per cent). It should be noted that other mechanical cultivations aimed to control pests (slugs and leatherjackets) are reported in the seed bed cultivation risk management section.

Figure 45 IPM: Non-chemical control – 2017

Of the 119 holdings sampled, five (four per cent) were organic. It should also be noted that, even where pesticides are used, pesticide input into grass and fodder crops are far lower, per hectare, than any other crop system. This should be taken into account when considering the responses below.

Fifty one per cent of the growers surveyed stated that they targeted their pesticide applications to reduce pesticide use (Table 34, Figure 46). The most common method reported was use of spot treatments (44 per cent). Spot treatments (applying only to the affected area) were used to combat a range of grassland weeds including thistles, docks, nettles and ragwort. Weed wiping (direct herbicide application to weeds taller than the host crop) was used by 14 per cent of growers, for control of thistles, bracken rushes, nettles and docks. Ten per cent of growers reported that they reduced their dosage or frequency of applications where possible. A further three per cent decreased pesticide application by using drift reduction apparatus and three per cent by precision application systems.

In addition, 39 per cent of farmers stated that they followed anti-resistance strategies when using pesticides, to attempt to minimise the risk of pest resistance development (Table 34). This included 34 per cent minimising the number of pesticide applications used, five per cent using pesticides with multi-site modes of action and three per cent using a range of pesticides with multiple modes of action. Other growers (three per cent) stated that their agronomist provided advice about anti-resistance strategies.

Figure 46 IPM: Targeted pesticide application – 2017

An important aspect of IPM is monitoring the success of risk management and crop protection practices to continually improve regimes. Eighty two per cent of the growers stated that they monitored the success of their crop protection measures (Table 34, Figure 47). This included 54 per cent conducting a regular review with their agronomist, 43 per cent conducting regular self-inspection and 11 per cent monitoring yields as a measure of crop protection success. In addition, lower proportions conducted a seasonal review of crop protection practice (three per cent), used precision technology (in field yield mapping, one per cent) or reviewed input costs (one per cent).

Figure 47 IPM: Monitoring success of crop protection measures – 2017

Note: 'other' is monitoring crop input costs