The Cypress aphids in the South of France.

In the South of France, Cinara (Cupressobium) cupressi, the main Cypress aphid, has been studied during 6 years on a mixed hedgerow in which Cupressus sempervirens and C. arizonica had been planted alternatively. In the area, this monoecious aphid is anholcyclic and heavily attended by ants. Continuous observation of the trees and of the colonies allowed a description of the population dynamics and the characterization of the damages. The two cypress species are regularly attacked, but the aphid appears earlier, remains longer and is more abundant on C. sempervirens, than on C. arizonica. The distribution of the colonies among trees is contagious. Some trees or groups of trees are attacked more frequently and/or present colonies earlier, suggesting that the tight interaction with ants may induce hivernation and early attack in some places.

New urban trees/pests interactions in Europe.

The tree species have long been chosen for street use on the ground of the following criteria: they should be easy and inexpensive to produce, they had to be hardy and withstand stresses and finally they should not bear undesirable pests. Recently, in order to bypass pests and diseases problems that could have arisen, or simply to introduce aesthetic changes, more and more exotic tree species have been used. Some inappropriate practices were developed, for instance the transport of cuttings or of adult plants with soil, sometimes on long distances. Such practices and the increase of international trading resulted in an exponential growth of the unintentional introductions of new pests. In this fast-changing situation, some street-trees are abandoned or doomed, even before being used as such. The best solution for this problem should be classical biological control, which consists in the safe acclimatization of specific natural enemies of introduced pests; this method should be used systematically on a larger scale.

Weed control in rice with metham-sodium.

Metam-sodium is a soil fumigant with herbicidal properties. A field experiment was conducted in 2000 at Copiano (Pavia, Italy) to determine the efficacy of three rates of metam-sodium (300, 450 and 600 l/ha) at three different planting times (5, 12 and 18 days after chemical treatments) for the control of weeds in rice cultivation. The study mainly focused on the control of red rice (Oryza sativa var. selvatica), a weed which is worldwide distributed in rice fields and difficult to eradicate Test design was a split-plot with four replications. The main plot size was 13, 5 by 15 m and the subplot size was 13, 5 by 5 m. The chemical treatments were carried out as pre-sowing. Two days after chemical treatments, all field plots were flooded with 10 cm of water as practiced locally. An early variety of rice (Loto) was sown at 150 kg/ha. Weed control was visually evaluated as a percentage of ground covering by all weeds and by each weed individually at three, four and five weeks after treatments. Observations were made also on rice selectivity, and rice grain yield was assessed at the end. Metam-sodium did not injure the rice plants. Metam-sodium at 450 l/ha controlled 100%, 97% and 92% of red rice at the first, second and third observations, respectively. Good results were also obtained with metam-sodium at 300 and 600 l/ha, which controlled 94 to 82% of red rice during the season. Echinochloa crus-galli was better controlled with the higher rates of metam-sodium, particularly in the early part of the season. Metam-sodium did not show enough efficacy in this study against Heteranthera reniformis, Bulboschoenus maritimus and Lindernia spp. The best rice grain yield was obtained with all rates of metam-sodium, when rice was sown 5 days after treatment.

Aphid pests of strawberry crops and their parasitoids in France.

The pest status of aphids on strawberry crops has changed with time. They were mainly considered with respect to virus transmission. Now, they are rather considered as sap-feeders and honeydew producers. As such, low populations regulated by natural enemies can be tolerated and systematic use of insecticides avoided. A survey of the species present in the different areas of production has been undertaken during 1999 and 2000 in France. During this survey, well known species of the strawberry crops have been found, like Chaetosiphon fragaefolii, Aphis forbesi or Acyrthosiphon rogersii. Widely polyphagous species like Aphis gossypii, Aulacorthum solani, Myzus ascalonicus or Macrosiphum euphorbiae were also present quite often. Eventually, aphids of the Rosaceae, not considered before as important pests of the strawberries, like Rhodobium porosum, have also been found in many different areas. The biology of the different species and their natural enemies have to be taken into account with respect to integrated control of strawberry pests.