AGRICULTURAL scientists are busy modelling the various changes to be thrown up if carbon dioxide (CO2) levels continue to rise at levels anticipated.
In cropping systems there will be good and bad aspects of increased CO2 levels.
Plants will grow faster and more vigourously, but crop quality will be lower.
It is a similar story when it comes to insect pests in crop, with some positive and some negative news.
A Victorian scientist has found there may be lower burdens of aphids in-crop, but said damage inflicted per aphid may be increased as they have to consume more of the plant due to the plant’s lower nutritional quality.
Piotr Trębicki, Agriculture Victoria, said aphids will feed more to make up for the lower-quality plants that are expected to grow under the CO2 levelspredicted to be in the atmosphere by 2050.
Dr Trębicki said the complex interactions between plants, insect pests and viruses under future climate conditions would have implications for plant disease severity and food crop production.
He said the study investigated how increasing CO2 concentration affects wheat, a virus pathogen and the aphid vector spreading the virus.
The authors studied insect biology on wheat plants exposed to increased CO2 levels, predicted for 2050, in the presence and absence of the Barley yellow dwarf virus.
Insect pests and plant diseases can decimate crop production when not treated and even with current control measures, which are costly and hazardous to the environment, yield losses are still substantial.
“In a not-too-distant future, atmospheric CO2 concentration will be double those from the preindustrial revolution,” Dr Trębicki said.
Due to the reduced plant quality under elevated CO2, aphid offspring production decreased but to recompense the lower quality aphids are forced to feed more.
The increased feeding will lead to greater plant damage.
“It is highly complex. On the one hand, less aphids are good news, but on the other, there will be more aphid damage, which is bad news.”