Monitoring and early detection of grape clusterworm, Lobesia botrana, by using pheromone trap in Beida vineyards.

Master's Thesis in Entomology

Monitoring and forecasting of grape cluster worm, Lobesia botrana, using pheromone trap in Baida vineyards

Abstract:

Pers is one of the most important producing provinces It is the country's grape. Beyza region, one of the functions of Sepidan city, has a very significant contribution in the amount of grape production in Fars province. The grape clusterworm, Lobesia botrana (Denis & Schiffermüller 1775), is one of the important and inhibiting factors of production in this area, which is unavoidable at least one or two times of chemical control. Therefore, it seems necessary to monitor and forecast this pest in the region in order to accurately determine the time of spraying and increase its efficiency. For this purpose, for two consecutive years (2013 and 2014), from the beginning of April until the moths disappeared in the garden, pheromone traps were installed at a height of 1.5 meters from the ground in the crown of the tree in three stations of Baida vineyards and they were visited once every 5 days and the pheromones were changed every 15 days. In these two years, the trend of pest population changes was monitored and analyzed with the help of pheromone traps. Also, the minimum and maximum day and night temperatures of 12 years (from 1381 to 1392) were collected from the General Department of Meteorology of Zarghan city and the average minimum and maximum temperatures were calculated for all days of the year. Then, the day-degree effective in the growth and development of the grape cluster worm was calculated in the form of a sinusoidal method. Finally, by using the two-year results obtained from the sampling, the effective day-degree calculated by a sinusoidal method and combining these two sets - the number of pest generations, the time period of emergence and peak flight of the generations, and the best time to spray against the pest - was estimated and concluded. and the period of emergence and peak flight of full insects in the same generations and the effective temperature calculated for these events in two years were very close to each other. The first generation of complete insects appeared with a small population and scattered from the end of April to the end of May. This generation did not have a significant population and its peak flight was not well recognized. The calculated heat demand in the time range of the occurrence of this generation was estimated to be 230 to 525 days-degree Celsius. The second generation of complete insects appeared in the period of two months of June and July, but its emergence and occurrence was very impressive from June 20 to July 20 (30 days). The heat requirement calculated in the time range of the significant occurrence of this generation and its flight peak was estimated to be 780-1260 and 960-1050 degree-days, respectively. The third generation of complete insects appeared in the period of two months from August to September, but in the period from August 20 to September 20 (30 days), its occurrence was very significant, and in the middle of this period, there was always a large population. Then, from the end of the second decade of Shahrivar, the population of the pest decreased and disappeared in the first decade of Mehr.

The heat requirement calculated in the time range of the significant occurrence of this generation and its peak flight was estimated as 1775 to 2235 and 1900 to 2000 days-degree Celsius, respectively. According to the results obtained, the right time to fight the first generation was not well defined, but for the second and third generations, if the amount of hunting traps indicates the abundance of the pest, late June to early July and late August to early September, respectively, is the best time to fight the pest.

Key words: Grapes, beza, piesh, grape clusterworm, day-degree

Importance of research

Grapes are one of the most valuable garden products whose production is very important in Iran and the world. Iran is considered one of the most important grape growing areas in the world due to its geographical and climatic conditions. According to FAO[1], in 2012, the world production of grapes is 58 million tons, of which 2 to 3 million tons are the share of Iran. The total area under grape cultivation in Iran is equal to 330 thousand hectares (240 thousand irrigated hectares and 90 thousand dryland hectares). Among the grape-growing regions of the country, Fars province has the largest cultivated area in the country with 76 thousand hectares.According to the statistics of the Ministry of Jihad and Agriculture in 2013, the area under cultivation of grapes in Fars province is 76 thousand hectares (72 thousand fertile hectares and 4 thousand non-fertile hectares), the amount of production of this product in Fars province is 550 thousand tons and the average yield of grapes per area is 8 tons per hectare. Beyza region with 1535 hectares of cultivated area is very important in the production of grapes in Fars province.

Grape clusterworm is considered one of the key pests of grapes in most parts of the country and Fars province. It attacks the grapevine every year and causes a lot of quantitative and qualitative damage to this product, which causes the product to fall and reduce its marketability. In many areas, the chemical fight against this pest is a necessity, but on the other hand, the indiscriminate and unplanned use of chemical poisons increases the possibility of resistance in the pest and will lead to other side effects such as the destruction of natural enemies, environmental pollution, the increase of poison residue on the fruit and the threat to the health of consumers.

So the fight against this pest must be done in such a way that both the pest is controlled to a significant extent and Its bad and unwanted effects on the environment and consumers' health should be minimized. Achieving such goals is possible when the pest is monitored and the best time for chemical combat against it is determined. If the monitoring is accurate, it can be used in damage prevention and pest control (Fadamiro[2], 2004). Without foreknowledge, it is difficult to judge the use of chemical poisons.

The effectiveness of foreknowledge depends more on the type of monitoring. Pheromone traps are very useful tools for monitoring biological processes and pest damage. Normally, insects in nature communicate with each other with the help of chemicals. For example, in the stages of mating and mating, one of the pairs disperses chemicals in nature, and the opposite sex receives these substances and goes to the source of dispersion. Today, these substances are known in many insects and have been artificially made in laboratories. Therefore, these substances can be used in the form of sex pheromone traps to investigate the life process of the pest in an environment and monitor the time of emergence of generations, the different biological stages of each generation and the peak of the emergence of complete insects. Finally, by monitoring the pest and predicting the biological process and its damage, the time of the chemical fight against the pest can be determined more accurately and the number of unnecessary sprayings can be avoided. This will lead to better protection of the crop, reducing the consumption of pesticides and reducing the economic costs for farmers (Weitzgall [3] et al., 2000).

This research was based on this in the Beida region of Fars to achieve the following goals:

Determination of the number of generations of grape clusterworm.

Determining the time of the appearance of the first complete insects in different generations, especially for the first generation.

Determining the peak flight time of complete insects in different generations.

Finding a logical relationship between the ambient temperature and the time of the appearance of the first complete insects and their peak flight.

By conducting this research and achieving the aforementioned goals It is possible to more accurately predict the time of chemical fight against grape clusterworm and recommend it to gardeners. Beyza as a part of this province is of great importance for producing grapes. Lobesia botrana (Denis & Schiffermüller 1775) is one of the most pernicious pests which decrease product quality and quantity in this region and once or twice chemical spraying is required to protect products. It seems to be necessary monitoring and forecasting pest to apply spraying in appropriate time and increase spraying efficiency.