ENVIRONMENT: Pesticides and new crops could spell the end for this insect. Now it seems our gardens could be their last refuge.

Britain's native bumblebee is under serious threat and gardeners were today urged to help save the species by a leading conservation charity and the Government's wildlife advisers.

The National Trust and English Nature warned that intensive farming methods with high use of pesticides and a decrease in the number of insect pollinated crops has led to a drastic fall in bumblebee numbers over the past 70 years, with one species nearly driven to extinction.

As a result gardens are now becoming increasingly important refuges for bumblebees and gardeners have a vital role to play in creating the right habitat to help the bees survive.

Fiona Reynolds, director general of the National Trust, said: "Without wild bees our gardens would be sterile places but we do not always give enough thought to how we manage our gardens to encourage these beneficial insects.

"Every garden counts in the wildlife stakes, whether large or small, urban or rural, with over 15 million gardens across the country, gardeners collectively can make a huge difference."

The National Trust and English Nature will be promoting the bumblebee and wildlife in gardens at the Chelsea Flower Show next week.

Many gardeners mistakenly think that all flowers are beneficial to bees when in fact many modern hybrids are sterile and lack the pollen and nectar that are vital for the survival of native insects.

The National Trust stand at the Chelsea Flower Show will feature a range of plants, such as simple "cottage garden" varieties and herbs, that attract bees, butterflies and a host of other wildlife.

There will be other top tips on how to create a wildlife haven without turning your garden into a wilderness.

Through its Gardens Initiative, English Nature is encouraging people to manage their gardens more sensitively for wildlife and will be launching a new leaflet "Help the Bumblebee" which visitors can pick up from the National Trust's stand.

A common misunderstanding is that bumblebees are aggressive.

This unfortunate mistake is usually caused by confusing bumblebees with wasps and honey bees and results in large numbers of bumblebees nests being unnecessarily destroyed each year.

In fact, these harmless insects are more likely to roll over on their backs and wave their legs in the air than sting you.

Sir Martin Doughty, of English Nature said "The bumblebee is right at the heart of a healthy garden.

"These busy insects carry pollen from plant to plant and without them we would not have as many beautiful flowers and delicious soft fruits.

"With a bit of extra care and suitable planting you will provide these tireless workers with a good home. Then sit back and admire the view whilst nature benefits too."

To help identify the significance of formal, historic gardens as wildlife habitats, this summer the National Trust will begin the first ever detailed survey of wildlife in its gardens.

The Trust's Wildlife in Gardens Initiative aims to celebrate and where practical, enhance the role of historic gardens in nature conservation.

As part of this initiative and in recognition of the importance of bees to gardens, the Trust will be finding out what species of wild bee occur in many of its gardens this summer.

It is likely that some Trust gardens are strongholds for rare and declining bees.

Wild bee experts are being brought in to search for scarce species and the discovery of entomological gold is anticipated.

BEES VITAL TO GROWING CROPS

Bees are the single most important pollinator in our gardens and without them many plants would fail to produce fruits, vegetables and flowers.

Bee numbers have fallen drastically, more than any other insect.

There are more than 250 different kinds of wild bee in the UK and 25% of these are rare or threatened with extinction.

There are around 24 species of bumblebee in the UK.

Three species of bumblebee and at least seven other species of bee have become extinct in the UK in the last 150 years.

Around 80% of the food we eat comes from crops that have been pollinated by bees.

All bees feed their brood on pollen. Some species rely on pollen from one species of flower, others will take pollen from a range of flower species. Adult bees feed on nectar.

Most bees are "solitary" with each female making her own nest separately.

Bees may forage over several kilometres if necessary.

A full pollen load may be gathered in only 15 minutes in areas of good forage but may take up to 90 minutes in areas of poor forage.