Large Scale Insecticide Spraying Needed to End Locust Plague in Madagascar


Locust Swarm, Madagascar

For many thousands of years, locust swarms have appeared in crop fields and farmers could only pray. Locust swarms may cover several hundred square kilometers during plagues and can contain 50 million locusts in each square kilometer. A locust plague has been building in Madagascar. Conditions for the locusts got better and better and then received a boost from a cyclone in February. The storm created ideal conditions for the locusts to breed. Without widespread spraying of insecticides, the locusts would devour most of Madagascar’s crops leading to millions of people going hungry.

“A locust control campaign has been launched by the United Nations and the Government of Madagascar to treat over 2 million hectares of infested areas in a bid to avert a food crisis that could affect some 13 million people in the island nation.

Aerial operations to identify and map out the areas requiring treatment by pesticides are expected to get underway this week, FAO said in a news release. In the meantime, ground surveys, conducted on a monthly basis since February, continue. Procurement of pesticides, vehicles and equipment for survey and control operations is also in progress. Spraying operations are expected to start in late October, after the onset of the rainy season.

An assessment mission carried out by FAO earlier this year found that rice and maize losses due to the locusts in some parts of the country vary from 40 to 70 per cent of the crop, with 100 per cent losses on certain plots. The agency estimates that losses in rice production could be up to 630,000 tonnes, or about 25 per cent of total demand for rice in Madagascar. Rice is the main staple in the country, where 80 per cent of the population lives on less than a dollar per day.”

Author: UN News Centre
Affiliation: The United Nations
Title: UN and Madagascar launch locust control campaign to avert food crisis
Source: UN News Centre. September 23, 2013. Available at:

Onion Plants Die Without Insecticide Treatments

Onion Maggot Damage

Onion Maggot Damage

100,000-300,000 onion maggots overwinter on every acre of onions in northern states. The average number of eggs laid by a single female in the spring is about 50. The emerging maggots seek out the roots and bulbs of onions and tunnel into the bulb. Maggots feed for two to three weeks. Damaged plants are usually so severely injured that they wilt, dry out and soon disappear.

“Management of onion maggot Delia antiqua is an integral component of onion production in the northern United States and Canada. There are three generations of D. antiqua per year in the northern United States and infestations of first-generation D. antiqua typically cause the most serious damage because maggot feeding kills seedlings. If onion seedlings are not protected with an insecticide applied during planting, D. antiqua can reduce plant stands by one-half to near 100%.”

Authors: B. Nault, J.Z. Zhao, R. Straub, J. Nyrop and M.L. Hessney.
Affiliation:  Department of Entomology, NYSAES, Cornell University.
Title: Onion Maggot (Diptera: Anthomyiidae) Resistance to Chlorpyrifos in New York Onion Fields.
Publication: Journal of Economic Entomology. 2006. 99(4):1375-1380.

30 million Insects per Acre in Chinese Rice Fields Means Growers Must Spray

Rice Stripe on Leaf

Rice Stripe on Leaf

Insects often transmit diseases when they fed on a crop plant. Rice is fed on by planthoppers which transmit viruses. In one outbreak in China, 30 million planthoppers were estimated to infest each of 50 million acres. Major losses were prevented thanks to insecticide sprays.

“Laodelphax striatellus Fallén (Hemoptera: Delphacidae) is an economically important sap-sucking pest in rice. The leaves infested by L. striatellus turn yellow, wilt, and even die, resulting in yield loss and quality reduction. In addition, L. striatellus transmits rice viral diseases such as Rice black-streaked dwarf virus and Rice stripe virus, which are two of the most serious diseases and often cause major yield losses. In recent years, the damage caused by L. striatellus feeding injury and the diseases transmitted by this planthopper has been increasing in China. When the outbreak occurred in Jiangsu and Anhui provinces in 2004 and 2005, the density of L. striatellus reached 30 million per acre, and 50 million acres of rice was infested, causing 30% of yield reduction in areas without pesticide treatment.”

Authors: C-X Duan1, J-M Wan1, H-Q Zhai2, Q Chen1, J-K Wang1, N Su1 and C-L Lei1
1Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China; 2Chinese Academy of Agricultural Sciences, Beijing, China
Title: Quantitative trait loci mapping of resistance to Laodelphax striatellus (Hemoptera: Delphacidae) in rice using recombinant inbred lines.
Publication: Journal of Economic Entomology. 2007. 100(4):1450-1455.

Japanese Consumers Have High Standards for Rice Quality Making Insecticide Use Necessary

Damaged Rice

Damaged Rice

Rice Bug

Rice Bug

The feeding of rice bugs on rice plants results in black marks on the rice grains. Japanese consumers demand perfect rice, which means that farmers must prevent the insects from feeding.

“A complex of Hemiptera, commonly referred to as rice bugs, are considered to be important insect pests in rice-growing regions of the world. Many species of Hemiptera, from families including Alydidae, Pentatomidae, Coreidae, and Miridae, have been reported as rice bugs.”

“Rice bugs cause yield loss, decrease the quality of grain, and reduce the germination rate. Among these problems, decrease in the quality of grain is considered to be the most important problem in Japanese rice. Infestations cause brown or black marks on the grain. Contamination of as little as 0.1% of such stained grain has reduced commercial value according to Japanese rice quality regulations, and thus the economic injury level is very low. This has led rice farmers to a dependence on insecticide use for rice bug control.”

Authors: H. Takeuchi1,2 and T. Watanabe1
Affiliation: 1Department of Entomology and Nematology, National Agricultural Research Center, Tsukuba, Japan; 2National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, Japan.
Title: Mortality factors of eggs of Leptocorisa chinensis (Hemiptera: Alydidae) in rice fields.
Publication: Journal of Economic Entomology. 2006. 99(2):366-372.