Reducing mosquito populations around the home... Mosquito problems may be eliminated when designing artificial water bodies such as garden ponds, and even reduced or eliminated in natural water bodies often by the use of simple landscaping techniques. Mosquitoes prefer to breed in the warm shallow margins of waterbodies, especially amongst emergent aquatic vegetation such as reeds and rushes. They are rarely found in steep sided ponds lacking vegetation because these tend to be both cooler, and also lack the readily accessible substrates from which they graze on algal and bacterial films which develop there. Further shading with terrestrial vegetation around the edges of the water body; (with fast growing species such as manuka (Leptospermum scoparium) and lemonwood (Pittosporum eugenioides) will further cool the water, and will also reduce the extent of the surface layers on which the mosquito larvae will feed. Planting of shorter growing species such as flax (Phormium tenax) and shrubs may suffice for smaller bodies. Introducing primitive aquatic plants called 'stoneworts' (Nitella and Chara) may also discourage mosquitoes from laying, and will thrive in these cooler, shaded waters. During this time natural insect predators of mosquito larvae will also begin arriving, such as dragonfly and damselfly larvae, back swimmers, and diving beetles. Fish such as common goldfish (Carassius auratus) may also be introduced if the waterbody is artificial, to help remove any remaining larvae. Care must be taken with any exotic species, however, to ensure that they do not escape into a natural waterway and cause damage e.g. through an overflow during a heavy rainfall event. Agitation of the water’s surface with devices such as a fountain or a waterfall will further deter the female mosquito from laying her eggs in your water body, and will also help to re-oxygenate the water, improving its quality for desirable aquatic life. These simple and easy modifications will make the waterbody less prone to mosquito breeding, aesthetically more pleasing, and also more suitable for native species which will 'mop up' any remaining larvae. These may include robust animals such as native snails (Physa and Potamopyrgus species) which will directly compete with larvae by grazing on the algal and bacterial surface films, or even some our little known native fishes such as the most common adult of the whitebait, inanga (Galaxias maculatus). A few of these mosquito larvae devouring animals may be legally collected as whitebait during the whitebait season, handled carefully in transit back home, and then simply introduced to grow. Remember to adhere to the whitebaiting regulations, they apply even when you are not eating your catch! Top-ups of the population may be by a simple white-baiting trip again to a river for a few more whitebait. Introductions of any fishes (native or otherwise) to a natural waterway, however, is both illegal (Freshwater Fisheries Regulation 1984), and may be more damaging than is recognised at the time e.g. loss of other species already present in that system. More information... Back to GAMBUSIA...