Bulawayo, Zimbabwe — As the sun sets over Robert Sayers' tomato farm in western Zimbabwe, he listens intently to the sounds of the African bush, searching for signs of menace.
The sound he fears most is the crack of a gunshot, which is being heard more and more in this troubled section of Zimbabwe.
Mr. Sayers sits calmly with an automatic weapon at his elbow while his wife and two children watch a two-year-old American program on television. He lists a half dozen white farmers and friends who have been killed by dissident blacks in the past year or so.
''You begin to wonder if you're just sitting here waiting for your turn,'' he says.
The rising tide of violence here is the most worrisome development, obscuring this young nation's achievements since it gained independence in 1980 as well as casting a dark shadow over its future prospects. The perpetrators of the violence are Zimbabwe's minority Ndebele-speaking blacks, who are displaying growing dissatisfaction with the predominantly Shona-speaking government headed by Prime Minister Robert Mugabe.
The growing conflict is helping scare off the nation's whites - vitally needed for their job skills - and generally straining the entire fabric of ethnic and racial relations. This perturbs Zimbabwe's well-wishers, who recognize that there must be relative consensus between the Shona and the Ndebele, and between blacks and whites for Zimbabwe to be a nation of stability and prosperity.
Observers make two points to put the level of dissident activity in perspective: (1)The government of Robert Mugabe remains firmly in power, and (2 )Zimbabwe is not in anything remotely like a state of civil war.
But diplomatic and military sources agree that over the past month rebel activity has grown ''more sophisticated'' and ''better organized'' and has a noticeable political flavor.
The wave of violence began early last year when Mr. Mugabe sacked Joshua Nkomo from the Cabinet for allegedly stockpiling arms to seize power. Ndebele-speaking backers of Nkomo then embarked on a campaign of robbery, murder , and kidnapping, despite public calls by Mr. Nkomo for them to cease.
In late December and early January, violence took a dramatic upturn with a series of attacks that resulted in seven deaths - black and white - bringing the total since Nkomo's sacking to 100 or so. The Army is still hunting for six foreign tourists kidnapped in July, although a military source says the Army has ''run out of leads.'' Security forces also are searching for a young white man kidnapped by dissidents on New Year's Eve.
Mugabe's response to the dissidents has been military. He seems to rely almost solely on the police and Army to root out trouble.
But so far the dissidents have only gained momentum, leading to sharper criticism of Mugabe's approach. ''There is never a pure military solution to this sort of problem,'' a diplomatic source says. Some say there must be a political answer, such as a Mugabe- Nkomo rapprochement or a campaign in the western area to discredit dissidents.
Security Minister Emerson Mun-angagwa charges South Africa has trained bandits and sent them into Zimbabwe to destabilize the country - charges South Africa denies.
The propaganda war between the two nations makes such claims difficult to substantiate. But observers in both countries worry that dissident activity could give South Africa ground for stirring dissent in Zimbabwe.
Although South Africa claims it is not trying to destabilize its neighbor, in at least one case members of the South African Defense Force were killed in Zimbabwe. South Africa claimed they were acting without authority.
The dissident activity appears to have generated new suspicions between whites and blacks in Zimbabwe. Many whites say they are being used as scapegoats because the government cannot contain the dissidents. For its part, the government appears to be increasingly concerned about the loyalty of whites.
These suspicions were highlighted in events following an attack last year on Zimbabwe's air base in Gweru. A number of senior white Air Force officers were arrested in connection with the attack, although the raid occurred at a time of wide dissident activity by blacks. A lawyer for two officers claimed they were tortured to extract confessions - a claim that led to the lawyer himself being charged.
Britain, concerned about human rights here, reportedly has refused to sell new aircraft to its former colony.
The Catholic Commission for Justice and Peace has made ''representations'' to Harare over ''areas of concern'' in human rights. But commission chairman Michael Auret says, ''Our concern is much less now than during the war years.''
Of most concern to Mr. Auret is the continuation of emergency powers laws inherited from the regime of former Prime Minister Ian Smith, a white. These laws have been so sweeping as to make anyone concerned about human rights ''anxious,'' Mr. Auret says.