Conservation & Ecology In addition, the fact that they work close
to trees means they are ideally placed to act as eyes and ears in support of our control programme. Thankfully, although we know of individuals who have been affected enough to seek medical advice, no serious OPM health issues or events have been reported in the UK. We believe this is because we and our partners, especially local authorities and major landowners, have learned from experience in continental Europe, and been proactive and effective in our efforts to keep the population down and the outbreak areas contained as much as possible. The main danger period is from April, when the larvae start emerging from eggs laid high in oak trees by adult moths the previous year, through to the end of summer. However, care should be exercised throughout the year, because ‘spent’ nests and shed skins can remain on trees - or on the ground if they have fallen out - and contain thousands of the hairs. Hairs, and nest and web material, can stick to bark and remain a threat there for some time.
Risk assessment
Protecting trees, people and animals from OPM exposure starts with vigilance and risk assessment. Professional groundstaff will naturally want to protect themselves and their oak trees, but they are also in the front line for discharging property owners’ duty of care to the users of their grounds. These can range from sports participants, spectators, students, teachers, hospital staff and patients to dog walkers, joggers and child minders and their infant charges. The best protection is:
- constant vigilance for signs of the pest, especially in spring and summer
- rapid action to remove it if it is identified
We therefore recommend that groundstaff in the known affected areas, and within two kilometres of them, incorporate into their routines a regular programme of inspecting oak trees for signs of OPM. In any case, anyone involved with pruning
or removing oak trees in OPM-affected areas must be familiar with OPM at its various
“ Protection
We advise anyone working on trees in the known infested areas, or within two kilometres of them, to wear PPE as a precaution. Key among PPE items are:
- filtering face masks and goggles - impermeable protective suits
- chemical-resistant gloves and rubber boots In addition, don’t forget that:
Don't jump to the conclusion that trees are free of the pest just because you can’t see anything
stages, and undertake a visual assessment to determine whether OPM is present. Key evidence of OPM can include:
- egg masses - although these are smaller than a fingernail and very difficult to see
- larvae (caterpillars) - typically clustering together or moving about in nose-to-tail processions
- silken webbing nests and trails on oak trunks and branches. These are white when fresh, but become discoloured with time. They can fall out of trees, so look for them on the ground as well
OPM evidence can be difficult or impossible to see early in the season, especially from the ground and in poor light, when the only presence might be egg masses or tiny, juvenile larvae high in the tree. So inspect oak trees closely - binoculars can be useful. And, if you find it, report it. (See ‘Legal requirements’ below.) And don’t jump to the conclusion that
trees are free of the pest just because you can’t see anything. Your mantra within or near the known affected areas, especially if you are planning to work on trees, must be: “don’t take the chance - wear PPE” (personal protective equipment).
- although the tree you are working on might not be an oak, its near neighbours might be - and, if they are infested, you can still be exposed to wind-blown hairs
- dogs are inquisitive, and their suffering can be severe if they get OPM hairs in their mouths and noses. So, if your dog accompanies you to work, don't expose it to the risk
With support from the Arboricultural
Association and the London Tree Officers' Association, we have published good- practice guidance for arborists, tree surgeons and pest control operators at
www.forestry.gov.uk/opm. We recommend that groundsmen and greenkeepers who work in or close to the affected areas familiarise themselves with this guidance, especially if they include tree care among their responsibilities. It contains summaries of:
- the risk assessment precautions to take before beginning work on trees which contain or might contain OPM
- the minimum recommended specification for PPE
- the key regulatory requirements for working with OPM-infested trees, covering topics such as notifications of infestations and handling oak material
Legal requirements
OPM is a legally notifiable tree pest, so suspected sightings must be reported to us or to your Local Council. No work may begin on a suspected infested tree until we have inspected it. If you have already started work on the
tree before seeing OPM evidence, you must stop work and report it. However, making a dangerous tree safe takes priority, but you must still report the suspected infestation as soon as possible. Clearly marking the affected tree can help
us to ensure the correct one is treated. If infestation is confirmed, we will issue a statutory Plant Health Notice to the owner
OPM in feeding cluster, showing partially stripped oak leaves
Crown copyright/Forestry Commission
An OPM cluster on an oak twig ©Martin Townsend
PC APRIL/MAY 2014 I 91
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156